Pleasanton Water

Does Your Water Taste or Smell Different?

Pleasanton receives its water from Zone 7 Water, the Tri-Valley's water retailer. During the summer months, algae blooms can cause changes in both the smell and sometimes taste of our drinking water. Although the water may have an unpleasant earthy odor or taste, the water is safe to drink and the changes are harmless, according to both Zone 7 Water Agency and the Dublin San Ramon Services District (DSRSD).

Summer Algae Blooms Cause Harmless Changes to Water

During the hot summer months, algae from the Delta can cause changes in both the taste and smell of our water. When water-borne algae are present in the water Zone 7 receives, powdered activated carbon is added to the treatment process. While the treatment reduces unpleasant taste and odors, it is not always 100 percent effective.

Zone 7 is upgrading its plants by adding ozone treatment over the next few years. Ozone is significantly more effective than other treatment technologies at treating algal byproducts that cause the unpleasant taste and odor are due in large part to geosmin and Methyl-Isoborneol (MIB). Both compounds can be detected by human noses at very low levels. The human nose is extremely sensitive to geosmin and MIB. If you poured a teaspoon of geosmin or MIB into the equivalent of 200 Olympic-sized swimming pools, you would still be able to smell it.

For more on this, see the Zone 7 Fact Sheet on Taste and Odor Changes Due to Algae or contact Gurpal Deol at or 925-454-5779.

How Water Quality is Monitored and Managed

Federal and state regulations require close monitoring of all water supplies. The water the district supplies to customers meets or exceeds all primary and secondary drinking water standards.

Many people work every day to protect the quality of our water.

Many agencies monitor water quality throughout the region. Here is a link to the City's 2016 Annual Water Quality Report.

In addition to Pleasanton's annual water quality testing, the Dublin San Ramon Services District (DSRSD) monitors water quality. 

Here is a link to DSRSD's most recent water quality report.