Skip to Main Content
Table 1

Summary statistics of water quality parameters in samples collected from private drinking water systems

Target water quality constituentStandardNumber of observationsMeanMedian90th percentilePercent exceeding
aArsenic, in mg/L MCL 0.010 mg/L 2,146 BDL BDL BDL 0.1% 
bCadmium, in mg/L  0.005 mg/L 2,144 BDL BDL BDL 0.6% 
aChromium, in mg/L  0.1 mg/L 2,144 BDL BDL 0.001 0.0% 
aFluoride, in mg/L  4.0 mg/L 2,146 BDL BDL BDL 0.4% 
aNitrate, mg/L  10 mg/L 2,146 1.5 BDL 4.2 1.3% 
aTotal coliforms, in cfu  ABSENT 2,143 – – – 46% 
aE. coli, in cfu  ABSENT 2,143 – – – 10% 
bCopper, in mg/L Action 1.3 mg/L 2,144 0.677 0.153 1.727 12% 
bLead, in mg/L Level 0.015 mg/L 2,144 0.022 0.004 0.027 19% 
bAluminum, in mg/L SMCL 0.05–0.2 mg/L 2,144 0.047 0.003 0.061 3.8% (12%*) 
aChloride, in mg/L  250 mg/L 1,378 14.3 5.4 31.4 0.2% 
aCopper, in mg/L  1.0 mg/L 2,144 0.677 0.153 1.727 15% 
aFluoride, in mg/L  2.0 mg/L 2,146 BDL BDL BDL 2.7% 
aIron, in mg/L  0.3 mg/L 2,146 0.142 0.008 0.234 8% 
aManganese, in mg/L  0.05 mg/L 2,146 0.032 0.002 0.049 10% 
apH, in standard units  6.5–8.5 2,146 7.1 7.2 8.0 (6.0c26% (23%**) 
bSilver, in mg/L  0.1 mg/L 2,144 BDL BDL BDL 0.0% 
aSulfate, in mg/L  250 mg/L 2,146 45.1 8.0 52.3 2.4% 
aTDS, in mg/L  500 mg/L 2,146 237.1 179.6 501.1 10% 
bZinc, in mg/L  5 mg/L 2,144 0.868 0.231 2.247 3.1% 
Target water quality constituentStandardNumber of observationsMeanMedian90th percentilePercent exceeding
aArsenic, in mg/L MCL 0.010 mg/L 2,146 BDL BDL BDL 0.1% 
bCadmium, in mg/L  0.005 mg/L 2,144 BDL BDL BDL 0.6% 
aChromium, in mg/L  0.1 mg/L 2,144 BDL BDL 0.001 0.0% 
aFluoride, in mg/L  4.0 mg/L 2,146 BDL BDL BDL 0.4% 
aNitrate, mg/L  10 mg/L 2,146 1.5 BDL 4.2 1.3% 
aTotal coliforms, in cfu  ABSENT 2,143 – – – 46% 
aE. coli, in cfu  ABSENT 2,143 – – – 10% 
bCopper, in mg/L Action 1.3 mg/L 2,144 0.677 0.153 1.727 12% 
bLead, in mg/L Level 0.015 mg/L 2,144 0.022 0.004 0.027 19% 
bAluminum, in mg/L SMCL 0.05–0.2 mg/L 2,144 0.047 0.003 0.061 3.8% (12%*) 
aChloride, in mg/L  250 mg/L 1,378 14.3 5.4 31.4 0.2% 
aCopper, in mg/L  1.0 mg/L 2,144 0.677 0.153 1.727 15% 
aFluoride, in mg/L  2.0 mg/L 2,146 BDL BDL BDL 2.7% 
aIron, in mg/L  0.3 mg/L 2,146 0.142 0.008 0.234 8% 
aManganese, in mg/L  0.05 mg/L 2,146 0.032 0.002 0.049 10% 
apH, in standard units  6.5–8.5 2,146 7.1 7.2 8.0 (6.0c26% (23%**) 
bSilver, in mg/L  0.1 mg/L 2,144 BDL BDL BDL 0.0% 
aSulfate, in mg/L  250 mg/L 2,146 45.1 8.0 52.3 2.4% 
aTDS, in mg/L  500 mg/L 2,146 237.1 179.6 501.1 10% 
bZinc, in mg/L  5 mg/L 2,144 0.868 0.231 2.247 3.1% 

MCL: Maximum Contaminant Level – associated with risk to human health; SMCL: Secondary Maximum Contaminant Level – associated with aesthetic considerations; BDL: below detection limit; cfu: colony forming units.

aTotal concentration measured in the flushed sample.

bTotal concentration measured in the first draw.

c10th percentile.

*Percent above 0.05 mg/L.

**Percent below pH of 6.5.

Close Modal

or Create an Account

Close Modal
Close Modal