Water quality

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.

Ninety percent of EBMUD's water comes from the 578-square mile watershed of the Mokelumne River on the western slope of the Sierra Nevada.

Every day of the year EBMUD's laboratory tests water samples to ensure that water quality meets federal 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. 

Annual water quality report 

EBMUD is pleased to report that in 2024 your drinking water quality surpassed every state and federal requirement that safeguards public health. If you would like a report mailed to you, please email us or call 866-403-2683. 

Each year EBMUD produces a water quality report . The annual report is usually available the following spring. In addition, we provide a 6-month update each fall that includes  water quality data for the first half of the calendar year. 

The annual water quality report includes information about contaminants that we've detected during the year. This is a regulatory requirement. However, we monitor for many additional parameters; most of them are not detected in our water. We produce an "all parameters" data table which is a list of everything we've monitored during the calendar year. 

Previous years' reports can be viewed on the Archives page. The 2024 report will be available in Spanish and Chinese by summer of 2025.

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.

Take a virtual tour of Orinda Water Treatment Plant.

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.

Public Health Goals Report

Every three years, the District is required to prepare a report with information about any contaminants detected above the state's Public Health Goals (PHGs). PHGs are non-enforceable standards set at very low levels that pose no significant health risk. We are also required to hold a public hearing at which the report is discussed, and receive public comment. The most recent report was discussed at the August 9, 2022 Board of Directors public meeting.