## Abstract

This article has been made Open Access thanks to the generous support of a global network of libraries as part of the Knowledge Unlatched Select initiative.

## INTRODUCTION

While the Flint Water Crisis has elevated national concerns about water lead exposure (Hanna-Attisha et al. 2016), there have been other high profile contamination events that caused serious childhood lead exposure (Edwards & Dudi 2004; Edwards & Triantafyllidou 2007; Masters & Edwards 2015). For instance, the 2001–2004 Washington DC Lead Crisis went largely unreported to the public for 4 years, caused hundreds of cases of elevated blood lead over the old CDC level of concern (10 μg/dL), and was associated with increased fetal death and miscarriage rates (Edwards et al. 2009; Edwards 2014b). Although a perfect comparison is not possible due to differences in sampling pools and methods, available data (Figure 1) suggest that the Washington DC first draw water lead levels (WLLs) were much higher than Flint (Edwards et al. 2009; Pieper et al. 2018a). However, it is important to note that first draw samples (i.e., samples collected after 6+ h of stagnation) do not always represent the worst-case WLLs, as these samples do not adequately characterize lead release in the particulate form or from LSLs (Edwards & Dudi 2004; Del Toral et al. 2013; Clark et al. 2014; Pieper et al. 2015a, 2017; Katner et al. 2018). Learning from these and other water lead contamination events can help avoid future problems during water crises, action level exceedances, and harmful exposures that occur in cities that meet the LCR.

Figure 1

Representative histogram of WLLs during the Flint and Washington DC lead in water crises (Edwards et al. 2009; Pieper et al. 2018a).

Figure 1

Representative histogram of WLLs during the Flint and Washington DC lead in water crises (Edwards et al. 2009; Pieper et al. 2018a).

The USEPA enacted the 1991 LCR to prevent widespread water lead exposure by reducing water corrosivity through corrosion control treatment (CCT) — corrosion control reduces the propensity of water to pick up lead when contacting plumbing infrastructure (U.S. EPA 1991). According to the LCR, water utilities must conduct the limited monitoring of high-risk homes under normal residential use conditions. High-risk homes are determined based on the age of structure and plumbing material composition, rather than selecting sites based on zonal variations in water corrosivity. If more than 10% of first draw samples exceed the lead action level of 15 μg/L, water utilities must optimize CCT, collect additional water samples, and notify the public. However, satisfying the LCR's action level requirements does not guarantee that a city's tap water is free of lead and is safe for all residents to consume (U.S. EPA 1991; Katner et al. 2016). The Natural Resources Defense Council revealed that in 2015, 5,363 water systems, serving more than 18 million US residents, had LCR health, monitoring, and/or reporting violations (Olson & Pullen Fedinick 2016). USA Today documented high WLLs in 350 schools and day-care centers between 2012 and 2015 (Ungar 2016), and also reported that 9,000 small water systems, serving almost 4 million rural residents, failed to test for lead in the past 6 years (Ungar & Nichols 2016). Moreover, private well users are not protected under the LCR, as private water systems (e.g., wells, springs, and cisterns) are not regulated by the USEPA (U.S. EPA 1991).

## CONCEPTUAL LEAD IN WATER EQUATION

The three key variables that influence the presence of lead in drinking water at homes are: (1) lead-bearing plumbing; (2) corrosive water; and (3) ineffective CCT (Figure 2). The worst-case combination of these variables will produce the highest levels of lead in drinking water, whereas correcting one or all of these variables can potentially reduce or prevent lead in drinking water. The equation is qualitative rather than quantitative and underscores factors that must be considered when addressing lead in water issues.

Figure 2

Figure 2

The use of lead in plumbing materials has been reduced over the years through USEPA regulations and industry best practices (Figure 3; Table S1, available with the online version of this paper). The 1986 Safe Drinking Water Act Amendments banned leaded and pure lead plumbing by requiring the installation of ‘lead-free’ plumbing (U.S. EPA 1989). However, ‘lead-free’ plumbing materials could still contain lead – up to 8% by weight until 2014 and a weighted average of 0.25% based on wetted surfaces thereafter (111th Congress 2011).

Figure 3

Lead-bearing plumbing components potentially used within drinking water systems. (a) Municipal water systems with responsibility split between the utility and the resident; (b) private wells which are solely the responsibility of the resident; and (c) home plumbing system which are solely the responsibility of the resident.

Figure 3

Lead-bearing plumbing components potentially used within drinking water systems. (a) Municipal water systems with responsibility split between the utility and the resident; (b) private wells which are solely the responsibility of the resident; and (c) home plumbing system which are solely the responsibility of the resident.

Although LSLs are the primary service line material of concern, galvanized iron service lines (Figure 3(a)) and well components (Figure 3(b)) can also serve as a lead source and have been attributed to water lead problems (Sandvig et al. 2008; Clark et al. 2015; Pieper et al. 2017, 2018a, 2018b). A galvanized iron pipe is an iron pipe with a protective zinc–lead ‘galvanized’ surface coating. This galvanized coating often contained between 0.5 and 1.4% lead by weight until 2014 (Clark et al. 2015). Lead can leach into water from a pre-2014 galvanized iron pipe and be distributed to the tap or accumulate in iron rust layers along the interior of the pipe – creating both short- and long-term water lead problems (Clark et al. 2015; Pieper et al. 2017, 2018b). Even new post-2014 ‘lead-free’ galvanized iron pipes (<0.25% lead in the surface coating) are still of concern due to the potential formation and remobilization of leaded rust scales (Pieper et al. 2016).

### Water corrosivity

Some waters are naturally corrosive, whereas other waters are naturally non-corrosive. There are several well-established water chemistry parameters that influence the corrosivity of drinking water such as dissolved oxygen, pH, water disinfectants, chloride-to-sulfate mass ratio, and alkalinity (Schock 1989, 1990; Triantafyllidou & Edwards 2007). These parameters are controlled and routinely monitored by the drinking water operators (see ‘Ineffective CCT’). Although lead cannot typically be detected by taste, smell, or sight in water, studies note that higher water corrosivity (and resulting WLLs) can sometimes associate with certain unpleasant or undesirable characteristics of the drinking water. For example, private well users who had obvious signs of corrosion (e.g., plumbing leaks), blue-green staining on plumbing fixtures, and described the taste of water as metallic were more likely to have copper concentrations and low water pH, which were correlated with high WLLs (Pieper et al. 2015b). Researchers have also occasionally linked the incidence of red/rusty water reports to elevated WLLs, as the corrosion of iron pipes may indirectly result in higher WLLs (Masters & Edwards 2015; Pieper et al. 2017, 2018a). While the presence of red/rusty water may be an indicator of lead in some situations, that is often not always the case (Tang et al. 2018).

### Ineffective CCT

Corrosion control by public water supplies involves the manipulation of pH, the adjustment of alkalinity, and/or the addition of corrosion inhibitors (e.g., phosphates or silicates), to reduce problems from lead pipes and other plumbing. However, residents reliant on private wells are responsible for implementing corrosion control, with associated responsibilities for monitoring and maintenance (Swistock et al. 2013; Pieper et al. 2015b). Although corrosion chemistry can be complex and dependent on plumbing materials (e.g., brass and solder), appropriate CCT can reduce lead in water through three dimensions of performance: (1) minimizing the dissolution of soluble lead and leaded scale layers by adding corrosion inhibitors to the water or increasing water pH and/or alkalinity (Figure S1(a)); (2) promoting the development of protective scale layers that reduce corrosion rates and the dissolution of soluble lead (Figure S1(b)); and (3) increasing the durability of leaded scale layers to prevent the destabilization and detachment of such layers to water (Figure S1(c)) (Figure S1 is available with the online version of this paper) (Schock 1989; Edwards & McNeill 2002). According to the LCR, any water utility serving ≥50,000 residents must have a state-approved optimized CCT plan (U.S. EPA 1991). CCT is only required in systems serving <50,000 residents when a utility exceeds the lead and/or copper action level during their required water sampling. The installation of CCT devices in private wells is limited and only corrects the water chemistry after treatment and only rarely the chemistry of water within the well plumbing (Swistock et al. 2013; Pieper et al. 2015a, 2015b).

The LCR requires the collection of first draw samples, which was once considered the worst-case scenario as dissolved lead concentrations increase with stagnation time. This 1 L first draw sample will typically capture 7.9 m (25.9 ft) of a 6.4 mm (0.25 in.) diameter pipe, which only includes household (or premise) plumbing and not lead from the service line. Researchers have concluded that single first draw samples may not capture the worst-case water lead, which is particularly true for homes with LSLs or homes with particulate lead problems (Edwards & Dudi 2004; Renner 2008; Del Toral et al. 2013; Clark et al. 2014; Pieper et al. 2015a, 2017; Katner et al. 2018). Other factors that can result in reduced detection of lead hazards include sampling in cold weather and at low flow rates, prior removal of aerator filters, pre-flushing the night before collection, and inadequate sample processing in the laboratory (Katner et al. 2016). In recognition of inherent weaknesses in the LCR sampling protocol, researchers are utilizing profile sampling methods to more accurately characterize the entire plumbing network, including the premise plumbing and service lines, and its detachment in response to higher flow rates (Del Toral et al. 2013; Clark et al. 2014; Pieper et al. 2015a, 2017). Thus, it is imperative that proper sampling protocols be used to quantify water lead accurately.

### Study objectives

The pervasiveness of lead in drinking water poses a significant public health threat, but exposure can be reduced or prevented almost completely, through the implementation of preventive measures. However, problems with monitoring, regulating, and remediating water lead have long been misunderstood due to the complexity of plumbing and corrosion control. With the USEPA's new ‘war on lead’ (Siegel 2018), it is imperative that simple but accurate scientific information be communicated effectively to a wide range of decision makers to reduce water lead exposures. This paper illustrates the application of an oversimplified ‘lead in the water equation’ to explain the key variables that control the presence of lead in water to lay audiences and presents factors to consider when selecting a household-level water lead remediation strategy. A case study methodology is used to inform practice based on the Flint Water Crisis. This work aims to provide public health practitioners, government officials, utility personnel, and concerned residents with a science-based model to inform communications, decision-making, and implementation of household-level avoidance strategies for lead from drinking water.

## METHODS

The application of the lead in the water equation is demonstrated through a case study of Flint, Michigan. Published and newly collected data from Flint were applied to evaluate the four primary water lead avoidance strategies: (1) flushing, (2) bottled water, (3) lead filters, and (4) LSL replacement (Table 1). The overall approach was to evaluate each strategy based on costs, limitations, and reductions in lead exposure (defined as WLL reductions or by water lead avoidance).

Table 1

Comparison of the four household-level lead remediation strategies used during the Flint Water Crisis

Reduction in WLLs (μg/L)

Financial costsa

Initial water lead value Intervention water lead value Percent of samples reduced <AL Cost of water per gallonb Installation and maintenance fees Non-exhaustive tangible and intangible impacts Potential impacts in Flint
Flushing Home of resident zeroc (1 home; 32 samples) First draw of 2,171 μg/L 3,550 μg/L
at 1 min
0% <$0.001 Volume of water flushed 1 min: 8.3 L (2.2 gal) 3 min: 24.9 L (6.6 gal) 5 min: 41.5 L (11.0 gal) 25 min: 207.5 L (55.0 gal) Price of water flushed$0.002 per 1-min flush
$0.006 per 3-min flush$0.01 per 5-min flush
$0.05 per 25-min flush Extra water use burden on water utility with morning and afternoon 3 min flush Daily: 2.2 million L (0.6 million gal) 30 days: 65 million L (17 million gal) Extra water use burden on household with morning and afternoon 3 min flush Daily:$0.01
30 days: $0.35 Other considerations: • - Cost of water for local utility • - Water scarcity challenges • - Water and wastewater treatment burden • - Infrastructure impacts • - Additional demand • - Educating residents on the protocol • - Prompting intervention adoption • - Developing education materials • - Perception of water safety 1,412 μg/L at 3 min 2,542 μg/L at 5 min 1,742 μg/L at 25 min Community-wide in August 2015d (268 homes; 3 samples per home) 90th percentile of 26.8 μg/L 11.3 μg/L at 1 min 94% 6.6 μg/L at 3 min 96% Community-wide in March 2016d (156 homes; 3 samples per home) 90th percentile of 22.4 μg/L 9.0 μg/L at 1 min 96% 3.2 μg/L at 3 min 99% Bottled water (costs and water lead estimates derived from three samples from each of five brands)e – <1 μg/L 100%$0.77–$8.32e Family of four drinking and cooking water needs Daily: 5 L (1.3 gal) 30 day: 600 L (159 gal) Price of bottled water 30 day:$122.05
Save $0.14 on water bill Plastic bottle to solid waste Daily: 5–40 bottles 30 days: 159–1,200 bottles Other considerations: • - Ongoing cost of bottled water • - Reduced water use from utility • - Resident may use less water (7 gal/day compared to 100 gal/day) • - Transportation to procurement/distribution of bottled water • - Trash/recycle burden • - Environmental and utility burden of discarded materials • - Benefit of the avoidance of other contaminants and taste/odor compounds • - Educating residents on bottled water use • - Prompting intervention adoption • - Developing education materials NSF 53 filters Home of Resident Zerof (1 unfiltered and 1 filtered sample) Influent of 13,200 μg/L 20 μg/L 0% <$0.001 Installation:
$15–50 for filter unit Maintenance:$10–15 per cartridge
Tap-mounted: replace filters every 3–4 months
Pitcher style: replace filters every 1–2 months
Other considerations:
• - Ongoing cost of filter replacements

• - Burden of getting initial and replacement filters

• - Environmental and utility burden of discarded filters

• - Benefit of the avoidance of other contaminants and taste/odor compounds

• - Educating residents on the protocol

• - Developing education materials

• - Perception of water safety

• - Perceived risk of microbial contamination

Community-wideg (241 homes; 1 unfiltered and 1 filtered sample per home) Unfiltered 90th percentile of 68 μg/L Filtered 90th percentile of <1 μg/L 100%
LSL replacemente(1 house; 18 samples) First draw of 2,171 μg/Lc 2.1 μg/L
first draw
<1 μg/L
at 1 min
32.4 μg/L
at 2 min
94% <$0.001 Estimated$2,800 to replace 25 ft. LSL and 192 ft. galvanized iron service line Other considerations:
• - Perception of safety

• - One-time high cost to utility

• - Cost to consumer for full LSLR

• - Removal, transportation, and disposal old materials

Reduction in WLLs (μg/L)

Financial costsa

Initial water lead value Intervention water lead value Percent of samples reduced <AL Cost of water per gallonb Installation and maintenance fees Non-exhaustive tangible and intangible impacts Potential impacts in Flint
Flushing Home of resident zeroc (1 home; 32 samples) First draw of 2,171 μg/L 3,550 μg/L
at 1 min
0% <$0.001 Volume of water flushed 1 min: 8.3 L (2.2 gal) 3 min: 24.9 L (6.6 gal) 5 min: 41.5 L (11.0 gal) 25 min: 207.5 L (55.0 gal) Price of water flushed$0.002 per 1-min flush
$0.006 per 3-min flush$0.01 per 5-min flush
$0.05 per 25-min flush Extra water use burden on water utility with morning and afternoon 3 min flush Daily: 2.2 million L (0.6 million gal) 30 days: 65 million L (17 million gal) Extra water use burden on household with morning and afternoon 3 min flush Daily:$0.01
30 days: $0.35 Other considerations: • - Cost of water for local utility • - Water scarcity challenges • - Water and wastewater treatment burden • - Infrastructure impacts • - Additional demand • - Educating residents on the protocol • - Prompting intervention adoption • - Developing education materials • - Perception of water safety 1,412 μg/L at 3 min 2,542 μg/L at 5 min 1,742 μg/L at 25 min Community-wide in August 2015d (268 homes; 3 samples per home) 90th percentile of 26.8 μg/L 11.3 μg/L at 1 min 94% 6.6 μg/L at 3 min 96% Community-wide in March 2016d (156 homes; 3 samples per home) 90th percentile of 22.4 μg/L 9.0 μg/L at 1 min 96% 3.2 μg/L at 3 min 99% Bottled water (costs and water lead estimates derived from three samples from each of five brands)e – <1 μg/L 100%$0.77–$8.32e Family of four drinking and cooking water needs Daily: 5 L (1.3 gal) 30 day: 600 L (159 gal) Price of bottled water 30 day:$122.05
Save $0.14 on water bill Plastic bottle to solid waste Daily: 5–40 bottles 30 days: 159–1,200 bottles Other considerations: • - Ongoing cost of bottled water • - Reduced water use from utility • - Resident may use less water (7 gal/day compared to 100 gal/day) • - Transportation to procurement/distribution of bottled water • - Trash/recycle burden • - Environmental and utility burden of discarded materials • - Benefit of the avoidance of other contaminants and taste/odor compounds • - Educating residents on bottled water use • - Prompting intervention adoption • - Developing education materials NSF 53 filters Home of Resident Zerof (1 unfiltered and 1 filtered sample) Influent of 13,200 μg/L 20 μg/L 0% <$0.001 Installation:
$15–50 for filter unit Maintenance:$10–15 per cartridge
Tap-mounted: replace filters every 3–4 months
Pitcher style: replace filters every 1–2 months
Other considerations:
• - Ongoing cost of filter replacements

• - Burden of getting initial and replacement filters

• - Environmental and utility burden of discarded filters

• - Benefit of the avoidance of other contaminants and taste/odor compounds

• - Educating residents on the protocol

• - Developing education materials

• - Perception of water safety

• - Perceived risk of microbial contamination

Community-wideg (241 homes; 1 unfiltered and 1 filtered sample per home) Unfiltered 90th percentile of 68 μg/L Filtered 90th percentile of <1 μg/L 100%
LSL replacemente(1 house; 18 samples) First draw of 2,171 μg/Lc 2.1 μg/L
first draw
<1 μg/L
at 1 min
32.4 μg/L
at 2 min
94% <$0.001 Estimated$2,800 to replace 25 ft. LSL and 192 ft. galvanized iron service line Other considerations:
• - Perception of safety

• - One-time high cost to utility

• - Cost to consumer for full LSLR

• - Removal, transportation, and disposal old materials

aIntervention costs (bottled water, filters, and LSL replacements) were provided to Flint residents at no cost at times during recovery.

bCost of water in Flint (RFC 2016).

cWater lead measured in April 2015 (Pieper et al. 2017).

dWater lead measured in August 2015 and March 2016 (Pieper et al. 2018a).

eMeasurements and data collected during this effort.

fFilter assessment at Virginia Tech in February 2016 (Edwards 2016).

gFilter assessment by USEPA in January 2016 (U.S. EPA 2016a).

### Consuming bottled water

The USEPA does not regulate bottled water quality, rather the U.S. Food and Drug Administration (FDA) is responsible for the safety and appropriate labeling of bottled water (FDA 2010). FDA's bottled water regulations do not pertain to approximately 60–70% of brands, as they are packaged and sold within the same state (Olson et al. 1999). There has been considerable debate regarding the health protectiveness of FDA's bottled water standards. But in terms of lead, the FDA has a lower allowable threshold than the USEPA – bottled water must contain less than 5 μg/L, which is a third of the action level (U.S. EPA 1991; FDA 2010).

To quantify WLLs in bottled water and potential bottled water lead exposure, our research team analyzed five brands distributed during the Flint Water Crisis (Deer Park, Great Value, Kroger, Member's Mark, and Nestle). All 15 samples contained non-detectable WLLs (<1 μg/L), demonstrating that these brands were safe for lead, and confirming that bottled water is a viable option that can be distributed during a water lead crisis. In addition, other corrosion-related metals (iron, copper, and zinc) were also below detectable levels (<10 μg/L). These brands differed mainly with respect to other water quality factors (e.g., sodium concentrations and water hardness) that can impact aesthetics (more information about bottled water quality and brands can be found at www.nsf.org). While bottled water provides a safe drinking water alternative in terms of lead, there are financial and environmental implications associated with its use. Moreover, the use of bottled water can impede the recovery of the system, as there will be a limited flow of distributed water with CCT in the premise plumbing and service lines.

Based on our review of popular brands available in grocery stores, a 1-gallon off the shelf container can cost between $0.77 and$1.75, while individual bottles can cost between $0.77 and$8.32 per gallon. Assuming the average person uses 5 L (1.3 gal) daily for all cooking and drinking purposes, a family of four will use 600 L (159 gal) of water over a 30-day period (U.S. Geological Survey 2016). Using the least expensive bottled water option, this family would spend $122.05 (not including tax) and only save$0.14 on water bill due to the conservation of 20 L/day (assuming $3.30 commodity charge per 14,195 L) (RFC 2016). As for waste generation, a family could generate 5–40 empty bottles daily and 159–1,200 empty plastic bottles monthly when using gallon and 16.9 ounce bottles, respectively. These estimates are consistent with a CNN profile of the Luster family in Flint (Zdanowicz 2016). Over 3 days, this family of three used approximately 4.8 gal for cooking, 3.6 gal for drinking water, and 6.9 gal for miscellaneous activities such as washing dishes and brushing teeth. While bottled water provides a safe alternative when tap water is lead-contaminated, this option may not be financially feasible or sustainable for low-income residents. Moreover, due to the inconvenience and expense, residents may use less water – the Luster family used 7 gal/day compared to an average of 100 gal/day (U.S. Geological Survey 2016). ### Using a filter certified to remove lead There are numerous treatment options available that are certified to remove specific health-related contaminants from drinking water (a consumer tool for identifying water filters certified to reduce lead can be found on the USEPA's website). NSF is one certifying body of water filters. NSF/ANSI 53 certified point-of-use (POU) filters can be a low-cost option to remediate water lead (NSF International 2015). POU filters are designed to treat water at a specific outlet, which limits the volume of water needed to be filtered. The activated carbon media sorb dissolved lead and trap particulate lead to reduce WLLs below 10 μg/L for water containing up to 150 μg/L lead (NSF International 2015). Thus, filters can be an effective remediation strategy if expired filter cartridges are regularly replaced. While POUs are available as tap-mounted, under-the-sink, and pour-through (pitcher filters) from numerous companies, tap-mounted units were recommended and distributed during the Flint Water Crisis (U.S. EPA 2016a). At the onset of the Flint Water Crisis, there were concerns regarding POU efficacy for homes with WLLs above the NSF/ANSI 53 threshold of 150 μg/L. Our team filtered the worst water lead sample from the home of Resident Zero (sample containing 13,200 μg/L) through an NSF/ANSI 53 certified ZeroWater™ lead filter and observed that 99.85% of the water lead was removed (Edwards 2016; Pieper et al. 2017). Although the filtered water was still above the USEPA action level on this extreme ‘worst-case’ sample, this experiment illustrated that POU filters are effective in dramatically reducing WLLs even under the most extreme conditions. The USEPA conducted additional NSF/ANSI 53 POU testing to examine the efficacy of Brita™ and Pur™ brand filters under more typical ‘worst-case’ WLLs in Flint (the 90th WLL of the unfiltered sample population was 68 μg/L) (U.S. EPA 2016a). Based on paired data from 241 Flint homes, POU filters were capable of removing lead in exceedance of 150 μg/L (reduced 4,080 to 0.9 μg/L). Moreover, in most homes, WLLs were reduced to non-reportable levels after filtration (the 90th WLL of the filtered sample population was <0.5 μg/L; high of 1.01 μg/L). Thus, the USEPA data clearly demonstrated that POU filters could effectively reduce the lead in tap water to well below both the action level and the bottled water standard, which is consistent with prior research (Deshommes et al. 2010, 2012). Although POU filters were distributed during the Flint Water Crisis at no cost to the residents (U.S. EPA 2016a), these devices are also readily available at local stores. Based on our review of popular brands available, tap-mounted POUs typically cost less than$50, with some models as low as $15. The filter capacity for most units was between 100 and 200 gal (projected to last 3–4 months), and the average cost for a replacement filter cartridge was$10–15. These POU filters cost between $25 and$35, with a replacement filter cartridge costing approximately $10–15. The pitcher style requires more frequent maintenance, as these units are only rated for 25–40 gal (projected to last 1–2 months). Over a 30-day period, the least expensive tap-mounted and pitcher style POU filters would cost only$10–15 in replacement cartridge needs, but this remediation requires an initial purchase of $15–50 for the filtration device. Thus, both POU styles provide a low-cost, effective remediation strategy for residents, but the ease of installation and filter replacement maintenance need to be considered when communicating this strategy. ### Removal of partial or full LSLs Exposure to water lead can be prevented by safely removing sources of lead. In the drinking water infrastructure, LSLs are the most concentrated source of lead and can directly contaminate drinking water. For example, assuming a family of four uses 400 gal of water per day, each foot of ¾″ lead pipe contains enough lead to raise every drop of water above the action level for more than 100 years (Edwards 2014a). Thus, replacing the LSL with a non-leaded alternative will greatly reduce water lead exposure. As previously described, the home of Resident Zero had high WLLs over a 26-min flushing period (>100 L) – the first draw and median WLLs were 2,171 and 1,747 μg/L, respectively (Pieper et al. 2017). In May 2015, the 25 ft LSL and 192 ft galvanized iron service lines present at the home of Resident Zero were replaced with a non-leaded pipe. The following week, a subsequent lead profile containing 18 sequential 1-L samples was collected at this home. There was a substantial decrease in WLLs even though there was no corrosion control in the system at that point – the first draw and median WLLs were 2.1 and 1.9 μg/L, respectively. However, there was a spike of 32.4 μg/L in the 17th liter of water, which is consistent with other literature suggesting short-term incident of high WLLs even after full service line replacements (Sandvig et al. 2008; Cartier et al. 2013). In addition, this practice still leaves lead sources within the home plumbing, which after the LSL is removed, becomes the source of 100% of the lead in water and can still far exceed the lead action level (Triantafyllidou & Edwards 2007; Triantafyllidou et al. 2007). Indeed, during the Flint Water Crisis citizen-led sampling events, the worst-case home sampled (WLL of 1,051 μg/L) had no lead pipe, rather the lead was derived from detaching pieces of lead solder (Pieper et al. 2018a). Efforts are currently underway to repair and replace the water infrastructure throughout Flint. It was estimated to take almost a decade to address all infrastructure replacement needs at the previous rate of repair, as only 224 of the 29,100 needed replacements had been completed between February and December 2016 (Derringer 2016; Moore 2016). Service line replacement can be a slow process due to its labor-intensive nature (e.g., destruction of streets and sidewalks, removal of complex landscaping, or tree root systems) (City of Flint 2016; Derringer 2016). The cost of service line replacements can also be cost prohibitive, especially for low-income communities (Katner et al. 2016). Additional environmental injustices can arise, as replacement decisions are at the discretion of the property owner, not renters. Through the USEPA funding, LSL and GSL replacements will be done at no cost to Flint residents (U.S. EPA 2017). However, most cities are not provided this kind of government support. Without state or federal assistance, the cost of a full line replacement ranges from$1,000 to $7,000 per home and may cost more depending on access constraints and other site-specific considerations (Lambrinidou & Edwards 2013). When residents are unable to pay for the replacement of the service line on their property, PLSLRs are conducted – a practice that disproportionately impacts low-income residents (Katner et al. 2016). Some water utilities are also ‘gifting’ the LSLs, which shift both the ownership and financial burden of LSL replacement to the customer (Kaplan & Hiar 2012). Removing the source of lead in drinking water infrastructure is an important step in preventing water lead exposure, but it is a time, labor, and financially intensive process. ## DISCUSSION When considering potential lead in water exposure and choosing household-level avoidance strategies, it is necessary to understand the protections afforded by regulations and public health guidance. The USEPA's current regulatory framework attempts to account for both water chemistry and infrastructure contributions to lead release by requiring sampling at consumers' taps (U.S. EPA 1991). However, lead sampling protocols were designed to inform regulatory oversight, not to characterize exposures or public health risks. Moreover, up to 10% of homes sampled during the LCR protocol can contain substantial lead as well as homes not sampled during LCR testing campaigns. Officials are also required to promote flushing on annual consumer confidence reports, and PLSLRs are still required under some non-compliance/exceedance circumstances despite evidence of the short-term-associated risks (Katner et al. 2016, 2018). While USEPA regulatory officials recognize the limitations of the LCR in protecting all individuals in a city from high water lead exposures, public health officials have long misinterpreted regulatory compliance as public health assurance. The CDC's guidance for investigating the homes of lead poisoned children does not require water lead testing if other sources of lead were found or if the city is meeting the LCR action level (U.S. CDC 2002). This recommendation has omitted water lead testing in LCR-compliant cities and overlooked a potential route of low-dose chronic lead exposure. These misinterpretations have led to missed opportunities to detect water lead issues and empower people with information on strategies that would allow them to take responsibility for independently addressing potential risks. The four household water lead avoidance strategies presented in this study reduced WLLs to some degree, but the effectiveness of these avoidance strategies will be site-specific. As explored in Flint, flushing reduced WLLs overall, but the household-level effectiveness was inconsistent. While city officials initially advised residents to flush their taps before using the water, this recommendation was replaced by using bottled water and/or an NSF/ANSI 53 lead filter. This work, along with others (U.S. EPA 2016a), have documented that both bottled water and lead filters are strategies that consistently provided safe drinking water. Although replacing the leaded plumbing removes the source of lead, as evident in Flint, this cannot be implemented at the height of a crisis. For communities concerned about lead in drinking water, building age and knowledge of plumbing materials will help determine the appropriate avoidance strategy, as this information can indicate likely types of leaded infrastructure present. For example, homes with pre-1986 plumbing are more likely to have leaded plumbing sources, including LSLs and lead solder, and may need more intensive interventions like plumbing replacements and avoidance strategies (e.g., bottled water and NSF/ANSI 53 filters). In contrast, lower risk homes, including homes built after 1986 (no LSLs or lead solder) and homes built after 2014 (<0.25% lead in the wetted surface), may not require plumbing replacements, but rather suffice with NSF/ANSI 53 filters. Although flushing is often promoted, it is important to know the presence and location of leaded plumbing materials, as it is not effective when particulate lead and LSLs are present in the system (Del Toral et al. 2013; Clark et al. 2014; Pieper et al. 2015a; Katner et al. 2018). Lastly, other potential variables impacting the residents and the city, such as financial burden, trash and recycling needs, and water conservation implications are difficult to estimate due to poor record keeping and limited research exploring such costs (Wang et al. 2018). ## CONCLUSION There is a critical need for proactive interventions to prevent lead exposure from drinking water instead of relying on reactive regulatory compliance actions that may not be sufficiently protective of public health. In this study, we illustrate the application of an overly simplistic lead in water equation to help understand that worst-case WLLs result from a combination of corrosive water, leaded drinking water infrastructure, and the absence of corrosion controls. Improving any of these conditions can reduce WLLs. The water lead avoidance strategies primarily focus on interventions at the household level to reduce potential water lead, including removal of leaded plumbing, remediation strategies such as flushing and filtration, and complete avoidance by switching to bottled water consumption. The optimal strategy for a given residence will be site-specific and based on a variety of factors and considerations. Thus, engaging with residents and the community will be critical to successful implementation. This work provides public health practitioners, government officials, utility personnel, and concerned residents with science-based information for informed communication, decision-making, and implementation of household-level avoidance strategies for lead from drinking water. ## ACKNOWLEDGEMENTS The research presented in this article was supported by the U.S. Environmental Protection Agency (#8399375) and by the National Institute of Food and Agriculture, U.S. Department of Agriculture (#2016-67012-24687). Data presented in this article were supported by the National Science Foundation through a Rapid Research Response grant (#1556258), a supplement to CBET Award (#1336650), and funding from the Community Foundation of Greater Flint. The authors would like to acknowledge the work of LeeAnne Walters (Resident Zero) and Miguel Del Toral (USEPA), for their assistance with water lead sampling, and Jeffrey Parks, William Rhoads, and Siddhartha Roy, for their assistance with sample collection and analysis. ## REFERENCES REFERENCES 111th Congress 2011 Reduction of Lead in Drinking Water Act . Washington, DC . . American Academy of Pediatrics 2016 Prevention of childhood lead toxicity . Pediatrics 138 ( 1 ), e20161493 . American Public Health Association, American Water Works Association, Water Environment Federation 1998 Standard Methods for the Examination of Water and Wastewater , 20th edn. American Public Health Association , Washington, DC , USA . Carmody S. 2015 Some residents blame the Flint River for city's drinking water problems. Is that fair? Michigan Radio. February 26, 2015 . . Cartier C. , Doré E. , Laroche L. , Nour S. , Edwards M. & Prévost M. 2013 Impact of treatment on Pb release from full and partially replaced harvested Lead Service Lines (LSLs) . Water Res. 47 ( 2 ), 661 671 . City of Flint 2016 Summary Report – Water Service Inventory and Pilot Replacement . . Clark B. , Masters S. & Edwards M. 2014 Profile sampling to characterize particulate lead risks in potable water . Environ. Sci. Technol. 48 ( 12 ), 6836 6843 . Clark B. N. , Masters S. V. & Edwards M. A. 2015 Lead release to drinking water from galvanized steel pipe coatings . Environ. Sci. Technol. 32 ( 8 ), 713 721 . Davis M. , Kolb C. , Reynolds L. , Rothstein E. & Sikkema K. 2016 Flint Water Advisory Task Force: Final Report . Office of Governor Rick Snyder, State of Michigan , Lansing, MI , USA . . Del Toral M. A. 2015 High Lead Levels in Flint, Michigan – Interim Report . U.S. Environmental Protection Agency Region V , Chicago, IL . . Del Toral M. A. , Porter A. & Schock M. R. 2013 Detection and evaluation of elevated lead release from service lines: a field study . Environ. Sci. Technol. 47 ( 16 ), 9300 9307 . Derringer N. 2016 Why Flint's lead pipe replacement costs so much, and moves so slowly. MLive. October 25, 2016 . . Deshommes E. , Zhang Y. , Gendron K. , Sauve S. , Edwards M. , Nour S. & Prevost M. 2010 Lead removal from tap water using POU devices . J. Am. Water Works Assoc. 102 ( 10 ), 91 105 . Deshommes E. , Nour S. , Richer B. , Cartier C. & Prévost M. 2012 POU devices in large buildings: lead removal and water quality . J. Am. Water Works Assoc. 104 ( 4 ), E282 E297 . Devine C. & Edwards M. 2016 Flint River Water is Very Corrosive to Lead, and Causing Lead Contamination in Homes . Flint Water Study Updates , Blacksburg, VA . . Edwards M. 2014a Designing sampling for targeting lead and copper: implications for exposure . In: Lecture Presented to the US Environmental Protection Agency National Drinking Water Advisory Group , September 18, 2014 . Edwards M. 2016 Frequently asked questions . . Edwards M. & Dudi A. 2004 Role of chlorine and chloramine in corrosion of lead-bearing plumbing materials . J. Am. Water Works Assoc. 96 ( 10 ), 69 81 . Edwards M. & McNeill L. S. 2002 Effect of phosphate inhibitors on lead release from pipes . J. Am. Water Works Assoc. 94 ( 3 ), 79 90 . Edwards M. & Triantafyllidou S. 2007 Chloride-to-sulfate mass ratio and lead leaching to water . J. Am. Water Works Assoc. 99 ( 7 ), 96 109 . Edwards M. , Triantafyllidou S. & Best D. 2009 Elevated blood lead in young children due to lead-contaminated drinking water: Washington, DC, 2001–2004 . Environ. Sci. Technol. 43 , 1618 1623 . Elfland C. , Paolo S. & Marc E. 2010 Lead-contaminated water from brass plumbing devices in new buildings . J. Am. Water Works Assoc. 102 ( 11 ), 66 76 . Felton R. 2014 Flint residents raise concerns over discolored water. Metro Times. August 13, 2014 . . Food and Drug Administration (FDA) 2010 Bottled Water Everywhere: Keeping it Safe . . Hanna-Attisha M. , LaChance J. , Sadler R. C. & Schnepp A. C. 2016 Elevated blood lead levels in children associated with the flint drinking water crisis: a spatial analysis of risk and public health response . Am. J. Public Health 106 ( 2 ), 283 290 . Kaplan S. & Hiar C. 2012 How an EPA project backfired, endangering drinking water with lead. NBC News. August 8, 2012 . . Katner A. , Pieper K. J. , Lambrinidou Y. , Brown K. , Hu C. , Mielke H. W. & Edwards M. 2016 Weaknesses in federal drinking water regulations and public health policies that impede lead poisoning prevention and environmental justice . Environ. Justice 9 ( 5 ), 109 117 . Katner A. , Pieper K. J. , Brown K. , Lin H. , Parks J. , Wang X. , Hu C. , Masters S. , Mielke H. W. & Edwards M. 2018 Effectiveness of prevailing flush guidelines to prevent water lead exposure in a compliant city with lead service lines . Int. J. Environ. Res. Public Health 15 ( 7 ), 1537 1559 . Kimbrough D. E. 2001 Brass corrosion and the LCR monitoring program . J. Am. Water Works Assoc. 93 ( 2 ), 81 91 . Lambrinidou Y. & Edwards M. 2013 Improving public policy through qualitative research: lessons from homeowners about lead service line replacement under the federal lead and copper rule . In: Presentation at 141st APHA Annual Meeting and Expo , November 2–6 , Boston, MA . Lytle D. A. & Schock M. R. 1996 Stagnation Time, Composition, pH, and Orthophosphate Effects on Metal Leaching From Brass. EPA 600/R-96-103 . National Risk Management Research Laboratory, Office of Research and Development , Washington, DC , USA . Masten S. J. , Davies S. H. & McElmurry S. P. 2016 Flint water crisis: what happened and why? J. Am. Water Works Assoc. 108 ( 12 ), 22 34 . Masters S. & Edwards M. 2015 Increased lead in water associated with iron corrosion . Environ. Eng. Sci. 32 ( 5 ), 361 369 . Michigan Department of Environmental Quality (MDEQ) 2015 Frequently asked questions: water lead levels in the City of Flint . . Moore K. 2016 Number of service lines that need replacing in Flint rises to 29,100, according to study. Michigan Press Release. December 1, 2016 . . National Toxicology Program 2012 NTP Monograph on Health Effects of Low-Level Lead . U.S. Department of Health and Human Services , Durham, NC , USA . . NSF International 2015 NSF/ANSI 53: Drinking Water Treatment Units – Health Effects . NSF International Standard/American National Standard , Ann Arbor, MI , USA . Olson E. D. & Pullen Fedinck K. 2016 What's in Your Water Flint and Beyond . Natural Resources Defense Council , New York, NY , USA . Olson E. D. , Poling D. & Solomon G. 1999 Bottled Water: Pure Drink or Pure Hype? Natural Resources Defense Council , New York, NY , USA . Pieper K. J. , Krometis L. , Gallagher D. , Benham B. & Edwards M. 2015a Profiling private water systems to identify patterns of waterborne lead exposure . Environ. Sci. Technol. 49 ( 21 ), 12697 12704 . Pieper K. J. , Krometis L. H. , Gallagher D. L. , Benham B. L. & Edwards M. 2015b Incidence of waterborne lead in private drinking water systems in Virginia . J. Water Health 13 ( 3 ), 897 908 . Pieper K. J. , Krometis L. & Edwards M. 2016 Quantifying lead leaching potential from plumbing exposed to aggressive waters . J. Am. Water Works Assoc. 108 ( 9 ), E458 E466 . Pieper K. J. , Tang M. & Edwards M. A. 2017 Flint Water Crisis caused by interrupted corrosion control: investigating ‘Ground Zero’ home . Environ. Sci. Technol. 51 ( 4 ), 2007 2014 . Pieper K. J. , Martin R. , Tang M. , Walters L. , Parks J. , Roy S. , Devine C. & Edwards M. A. 2018a Evaluating lead in water levels during the Flint Water Crisis . Environ. Sci. Technol. 52 ( 15 ), 8124 8132 . Pieper K. J. , Nystrom V. E. , Parks J. , Jennings K. , Faircloth H. , Morgan J. B. , Bruckner J. & Edwards M. 2018b Elevated lead in water of private wells poses health risks: case study in Macon County, North Carolina . Environ. Sci. Technol. 52 ( 7 ), 4350 4357 . Rabin R. 2008 The lead industry and lead water pipes ‘A modest campaign.’ . Am. J. Public Health 98 ( 9 ), 1584 1592 . Raftelis Financial Consultants (RFC) 2016 Flint Water Rate Analysis . State of Michigan Treasury Department , Lansing, MI . . Renner R. 2008 Pipe scales release hazardous metals into drinking water . Environ. Sci. Technol. 42 , 4241 4241 . Sandvig A. M. , Kwan P. , Kirmeyer G. , Maynard B. , Mast D. , Trussell R. , Trussell S. , Canter A. & Prescott A. 2008 Contribution of Service Line and Plumbing Fixtures to Lead and Copper Rule Compliance Issues . Water Environment Research Foundation , Denver, CO , USA . Schock M. R. 1989 Understanding corrosion control strategies for lead . J. Am. Water Works Assoc. 81 ( 7 ), 88 100 . Schock M. 1990 Causes of temporal variability of lead in domestic plumbing systems . Environ. Monit. Assess. 15 ( 1 ), 59 82 . Siegel J. 2018 EPA's Scott Pruitt declares ‘war on lead,’ three years after Flint water crisis began. Washington Examiner. January 23, 2018 . . Smith L. 2015 This mom helped uncover what was really going on with Flint's water. Michigan Radio. December 14, 2015 . . St Clair J. , Cartier C. , Triantafyllidou S. , Clark B. & Edwards M. 2015 Long-term behavior of simulated partial lead service line replacements . Environ. Eng. Sci. 33 , 53 64 . Swistock B. R. , Clemens S. , Sharpe W. E. & Rummel S. 2013 Water quality and management of private drinking water wells in Pennsylvania . J. Environ. Health 75 , 60 66 . Tang M. , Nystrom V. , Pieper K. , Parks J. , Little B. , Guilliams R. , Esqueda T. & Edwards M. 2018 The relationship between discolored water from corrosion of old iron pipe and source water conditions . Environ. Eng. Sci. 35 ( 9 ), 943 952 . Triantafyllidou S. & Edwards M. 2007 Critical evaluation of the NSF 61 Section 9 test water for lead . J. Am. Water Works Assoc. 99 , 133 143 . Triantafyllidou S. & Edwards M. 2012 Lead (Pb) in tap water and in blood: implications for lead exposure in the United States . Crit. Rev. Environ. Sci. Technol. 42 ( 13 ), 1297 1352 . Triantafyllidou S. , Parks J. & Edwards M. 2007 Lead particles in potable water . J. Am. Water Works Assoc. 99 ( 6 ), 107 117 . U.S. CDC 2002 Managing Elevated Blood Lead Levels Among Young Children: Recommendations from the Advisory Committee on Childhood Lead Poisoning Prevention . . U.S. CDC 2013 Sources of lead: water . Available from: https://www.cdc.gov/nceh/lead/tips/water.htm (accessed August 2018) . U.S. EPA 1989 The Lead Ban: Preventing the Use of Lead in Public Water Systems and Plumbing Used for Drinking Water . EPA 570/9-89-BBB . Office of Water , Washington, DC , USA . U.S. EPA 1991 Maximum contaminant level goals and national primary drinking water regulations for lead and copper; final rule . Fed. Reg. 56 ( 10 ), 26460 . U.S. EPA 2016a Flint, MI filter challenge assessment . . U.S. EPA 2016b Lead and Copper Rule Revisions: White Paper . . U.S. EPA 2017 EPA awards$100 million to Michigan for Flint water infrastructure upgrades
. .
U.S. Geological Survey
2016
Water questions & answers: How much water does the average person use at home per day? Available from: http://water.usgs.gov/edu/qa-home-percapita.html (accessed August 2018)
.
Ungar
L.
2016
Lead taints drinking water in hundreds of schools, day cares across USA. USA Today. March 17, 2016
. .
Ungar
L.
&
Nichols
M.
2016
4 million Americans could be drinking toxic water and would never know. USA Today. December 12, 2016
. .
Wang
T.
,
Kim
J.
&
Whelton
A. J.
2018
Management of plastic bottle and filter waste during the large-scale Flint Michigan lead contaminated drinking water incident
.
Resour. Conserv. Recycl.
140
,
115
124
.
Welter
G.
2016
Typical Kitchen faucet-use flow rates: implications for lead concentration sampling
.
J. Am. Water Works Assoc.
108
(
7
),
E374
E380
.
Zdanowicz
C.
2016
Flint family uses 151 bottles of water per day. CNN. March 7, 2016
. .

## Author notes

These authors contributed equally to the work.