Microbiological quality of chlorinated water after storage in ceramic pots

Household water treatment with sodium hypochlorite has been shown to reduce self-reported diarrheal disease in developing countries. Reported hypochlorite use, time since treatment, total chlorine residual (TCR), and E. coli concentration results from 589 household surveys in rural Kenya were analyzed to quantify the effect of exceeding recommended 24 hour post-treatment water storage time in ceramic pots. Exceeding storage time recommendations impacted treatment efficacy, as 87% of reported treaters with TCR ≥ 0.2 mg/L storing their water ≤ 24 hours met World Health Organization (WHO) E. coli guideline values, compared to 77% of reported treaters with TCR ≥ 0.2 mg/L storing water >24 hours (p = 0.024) and 7% of reported non-treaters. Implementing organizations face the trade-off between promoting treating water every 24 hours and accepting slightly compromised efficacy.