Contaminated drinking water is a leading cause of morbidity and mortality in low-income settings. Safe drinking water is of particular concern for HIV-positive mothers since many HIV-infected Zambian women choose replacement feeding and early cessation of breastfeeding of infants to minimize the risk of transmission of the virus. This study builds upon preliminary baseline research which determined that HIV-positive mothers would potentially benefit from an intervention that encourages HIV-positive mothers to treat their water at the household level.