In 2001, PDP initiated a finished drinking water monitoring survey in California and New York. In 2002, PDP expanded its water program to include additional geographic regions within the United States, including Colorado, Kansas, and Texas. In 2004, the program was retooled to sample paired raw and finished water. Through December 2011, samples have been collected by water treatment facilities that draw from surface water sources in 27 States plus the District of Columbia.

In 2007, a potable groundwater survey was started to test wells at farms and private residences in agricultural areas. In 2009, the groundwater program was expanded to include onsite wells at public and private schools and daycare centers across the Nation. Through December 2011, samples have been collected from 724 wells in 41 States plus the District of Columbia.

In 2010, a survey was started to test samples collected from municipal water facilities that draw from groundwater sources. Through December 2011, water samples have been collected from 14 facilities in 11 States.

The samples are mailed to PDP laboratories for multiresidue pesticide analyses. Data collected will be used to test assumptions and validate existing models used by EPA to incorporate finished drinking water into risk assessments and to make pesticide re-registration decisions.