Table 2. Water Source Definitions.

Drinking Water Source		Controls, N (%)	Cases, N (%)	Total, N (%)
Chlorinated	Piped water: chlorinated water from a centralized water treatment source, including some wells, that is piped into the home.	511 (84.5)	246 (80.4)	757 (83.1)
	Chlorinated well water: water from a non-centralized well that has been chlorinated either by the household or by community health workers called behvarz, who are responsible for community safe water and water quality testing in rural areas [49].	27 (4.5)	2 (0.7)	29 (3.2)
Unchlorinated	Unchlorinated well water: water obtained from an unchlorinated well that is not accessed through a pipe leading into the home. Wells can be personal sources owned by one household, or they can be shared.	11 (1.8)	22 (7.2)	33 (3.6)
	Surface water: water retrieved from rivers, lakes, springs, or other natural sources that is not accessed through a pipe leading into the home.	10 (1.7)	16 (5.2)	26 (2.9)
	Cistern water: rain water collected and stored in underground reservoirs which have little ventilation or exposure to outside contamination. Cisterns are maintained and owned by households, and are not shared sources. This water is not accessed through a pipe leading into the home.	46 (7.6)	19 (6.2)	65 (7.1)