Fundacion Cantaro Azul (FCA) is a non-profit organization in Baja California Sur, Mexico (BCS). Since 2006 FCA has piloted a safe drinking-water program in rural regions of BCS. The premise of their safe drinking-water programs has been the installation of household drinking-water disinfection systems which utilize an ultra-violet technology (UV) developed at the University of California, Berkeley. While the systems have been tested for safety and effectiveness at inactivating waterborne pathogens, FCA is interested in rigorously evaluating the impact of their safe drinking-water program at the population level. FCA is looking to expand their safe-water program during 2009 and 2010 to newly identified communities that lack safe-drinking water. In order to evaluate the community level effectiveness of their program FCA has agreed to randomize the timing of this expansion which will allow the lead investigators and key personal in this protocol to conduct a meaningful, scientific evaluation of the impact of their program through a randomized stepped wedge design.

The research described in this protocol has four (4) primary objectives:

1. To evaluate the impact the implementation of the safe drinking-water programs has on rates of gastrointestinal events in rural BCS communities;
2. To evaluate the impact of the safe drinking-water programs on concentrations of fecal contamination in household drinking-water in rural BCS communities;
3. To evaluate other-health and non-water impacts on communities where the safe-water programs are implemented, including school and work absenteeism, and health care costs;
4. To identify household, program and system design characteristics that affect user compliance with the disinfection strategies.

The investigators hypothesize that households that receive an UV based drinking-water disinfection system through the safe-water program will have reduced prevalence of gastrointestinal illness, and reductions in fecal contamination of household drinking-water, measured as concentrations of Escherichia Coli per 100 ml of water. Similarly, the investigators hypothesize that these communities will also have reduced health care costs, and school and work absenteeism due to the implementation of the safe drinking-water programs. The investigators further hypothesize that household level characteristics and specific program characteristics will differentially impact user compliance, measured as the sustained use of the systems over the course of the study. In order to evaluate the last hypothesis (Objective 4) two program variations will be rolled out to inform future programmatic decisions. A priori the investigators do not anticipate that these program variations will impact population measures for Objectives 1 and 2, but the investigators will explore these assumptions during analysis.

Twenty-five to thirty communities (400-600 households) have been identified by Fundacion Cantaro Azul (FCA) as communities that are appropriate for their safe water program. These communities were identified based on their sources of water (chemical and taste characteristics) and resource availability (access to electricity and lack of access to piped water). Fundacion Cantaro Azul is planning to expand their safe-drinking water programs to all 600 households in these communities. In order to allow for a meaningful evaluation of the impact of their program the organization has agreed to randomize the timing of implementation of the safe drinking-water program to eligible communities. This will allow independent researchers (the lead investigator and key personal in this protocol) to make household visits during the implementation of the programs and will further allow for a valid evaluation of the programs' impact using a stepped wedge study design. Through the stepped-wedge study design all communities, over a 12-15 month, period will be approached by Fundacion Cantaro Azul for promotional meetings; since no community will have received the intervention they will be acting as their own controls until the time they are approached by the organization. Randomizing the time at which a community is approached reduces bias and allows for meaningful evaluation of differences in outcomes due to the safe drinking-water program. As part of this study design a randomly assigned, predetermined number of rural BCS communities will be approached every two-months for enrollment in the safe water program by Fundacion Cantaro Azul, and thus 'cross-over' from the comparison group to the safe-water group. Within each of these crossover groups half of the clusters will receive a "Basic" program variation, and half will receive an "Enhance" program variation. This process will continue until all consenting households in the 25-30 communities have received a UV disinfection system, and related support through the safe drinking-water program. Field teams, trained and supervised by the lead investigator and key personal listed in this protocol, will conduct independent (from Fundacion Cantaro Azul) household visits to collect data on the outcomes of interest. During household visits structured interviews and water-quality sampling will be used to measure these outcomes (prevalence of gastrointestinal events, concentrations of E.coli in household drinking-water, school and work absenteeism and compliance with the disinfection strategy.) The stepped-wedge design will allow for evaluation of the impacts of the safe drinking-water programs while allowing the relatively small organization to manage the logistics of installing 600 household disinfection systems, in a manner consistent with their mission, commitments to regional governmental collaborators, and fiscal restraints.

Inclusion Criteria:

Communities:

1. are within the La Paz and Los Cabos counties of Baja California Sur, Mexico;
2. lack access to centrally treated drinking water distribution;
3. access drinking water sources (i.e. wells and springs) year round for household purposes

Exclusion Criteria:

Community source water:

1. contains levels arsenic that are below Mexican limits;
2. has taste characteristics (e.g. salinity) that are acceptable for drinking among community members.