Water Quality

photo of girl drinking a glass of water

One of the most important factors in water quality is the source: the purer the source, the better the water. EBMUD's primary water source is Sierra Nevada snowmelt.

Before water reaches your tap, EBMUD takes many steps to ensure its quality. This includes carefully managing and protecting watershed lands and reservoirs, treating the water, maintaining that quality through a complex system of distribution pipes, pumping plants and reservoirs, testing water samples in our lab and in the field, and addressing consumer concerns. 

Every day of the year EBMUD's laboratory tests water samples to ensure that water quality meets EPA and state standards, checking for trace organics like pesticides, metals, and microbes. These efforts ensure that all customers receive high-quality drinking water that meets or surpasses all state and federal regulatory requirements.

Where your Water Comes From

Ninety percent of EBMUD's water comes from the 577-square mile watershed of the Mokelumne River on the western slope of the Sierra Nevada. This area is mostly national forest, EBMUD-owned lands and other undeveloped lands little affected by human activity.

The Mokelumne watershed collects snowmelt from Alpine, Amador and Calaveras counties. The snowmelt flows into Pardee Reservoir near the town of Valley Springs. Three large aqueducts carry water more than 90 miles from Pardee Reservoir to the East Bay and protect it from pesticides, agricultural and urban runoff, municipal sewage and industrial discharges. When water demand is high or during times of operational need, EBMUD also draws water from protected local watersheds.

Annual Water Quality Report

In 2013, your drinking water met or surpassed every state and federal public health requirement.

If you would like a report mailed to you email us or call 510-986-7555.

Previous years' reports can be viewed on the Archives page.

The 2013 water quality report is available in English and in Spanish and the Chinese version will be available shortly. The document below is a PDF file which can be viewed and printed with Adobe Acrobat Reader, a free software.

Water Quality FAQs

Customers may have similar water quality concerns. Find answers to the most common water quality questions in our Frequently Asked Questions page.

If you still have questions, concerns or problems regarding water quality, such as taste, odor, appearance, etc., or if you have a water quality emergency, please contact us at 1-866-403-2683.

Water Treatment

Every drop of water that comes out of your tap is first treated at one of our treatment plants. EBMUD's six water treatment plants in the East Bay can filter and process more than 375 million gallons of water daily.

Water Sampling and Testing

In laboratories and in the field, EBMUD samples and tests your water extensively to make sure it is safe to drink. We look for more than 100 substances in the water including microorganisms, pesticides, herbicides, asbestos, lead, copper, petroleum products and by-products of industrial and water treatment processes. More than 20,000 annual laboratory tests ensure the safety of your drinking water.