The Sonoma County Water Agency (SCWA) provides wholesale water to over 600,000 residents in Sonoma and Marin Counties through public water systems such as cities and special districts. Each year SCWA sends these agencies detailed sampling results for each of their water sources. The agencies use this sampling data to produce the federally mandated "Consumer Confidence Report" which Santa Rosa calls the Water Quality Report. Many of the agencies including the City of Santa Rosa utilized local water well supplies that also must be analyzed. Those results are also included in their Consumer Confidence Reports. Santa Rosa's Water Quality Reports are at the link to the left. Below are the last six years of sampling data from the Sonoma County Water Agency and four years results from Santa Rosa's Farmers Lane Water Treatment Plant: