If local tap water looks white, the cause is air bubbles. This temporary change affects only the appearance of the water. The City's drinking water continues to meet all State and Federal water quality standards, has been property disinfected, and is safe to drink.
During January or February of each year, the City's regular source of water, the Hetch Hetchy Reservoir in the Sierra Nevada Mountains, is turned off so that maintenance and improvement projects can be carried out. During this time, the City instead receives water from the local Alameda County watershed. This local water is fed to the treatment plant at a higher-than-normal flow rate. As a result, very small air bubbles are added to the water during the treatment process.
The Hetch Hetchy Reservoir will again be providing water to City customers by the end of February 2008.