Lead and Copper

The City is required by the State Water Resources Control Board Lead and Copper Rule to sample every three years to determine if high levels of lead or copper are leaching into drinking water from home plumbing systems. We are pleased to report the July 2021 results. Lead was not detected at any of the 34 sampled homes, and the 90th percentile copper result was just 0.3 parts per million (ppm), well below the regulatory Action Level of 1.3 ppm.

View the Letter to Homeowners regarding Lead and Copper Test Results (PDF)

If present, elevated levels of lead can cause serious health problems, especially for pregnant women and young children. Lead in drinking water is primarily from materials and components associated with service lines and home plumbing. Unlike other regions of the U.S. where lead was prevalent, it was not the predominant construction material used in the City of Napa for water service installations. Years of monitoring show the existing public system pipe network does not contribute lead to the drinking water.