What’s in San Jose’s Tap Water?

Life in San Jose, California, means living with the energy of a thriving tech industry, warm climates, and good public infrastructure, including access to a stable water supply. However, many of its citizens are probably wondering what is actually coming out of the tap—particularly with the growing concern about tap water contamination that is sweeping the nation. If you are among those carefully monitoring the query, "What's in San Jose tap water?" then you are among the majority.

Sources of San Jose tap water include two water systems: San Jose Water Company (which supplies 1 million residents) and San Jose Municipal Water System (which supplies residents in zones such as Evergreen, North San Jose, and Alviso) of San Jose, CA, respectively. Both rely on a combination of water sources and are required by federal and state standards and policies.

However, “safe” under regulation does not automatically mean an absolute, clean presence that is completely worry-free. This is where outside reviews, including Environmental Working Group analyses, highlight the presence of problem chemicals even if they remain below the regulatory standard. This is where we can further investigate.

Understanding where the water comes from is important if we are to grasp what is in our glass. The water for San Jose comes from a wide range of sources:

Roughly half of the imported surface water comes from long-distance delivery via the Sierra Nevada range, distributed via the Delta, with processing by entities such as the Santa Clara Valley Water District , also known as Valley Water, or San Francisco Public Utilities Commission.

The second half of the water comes from underground aquifers in the Santa Clara Valley. This type of groundwater is filtered naturally but can absorb minerals and trace contaminants present in the ground.

Your drinking water is blended, disinfected (often by chloramine), and sometimes fluoride is added. It will promote reliability, especially in times of drought, but will also add some variability to flavor, hardness, and trace contaminant levels.

Yes. Government sanctions show that its tap water is safe and suitable for consumption. There are strict tests by both the EPA and California State Water Resources Control Board , and current reports indicate no violations of health-based standards.

However, the EWG believes that certain federal standards are indeed stale, having been unchanged for more than 20 years and not reflecting the latest scientific data regarding exposure dangers. Certain populations, including pregnant women, babies, kids, or immunocompromised individuals, require an added layer of care.

Chloramine taste/odor is common among many people in San Jose. This is not poisonous, though it makes tap water less preferred than bottled water.

San Jose Water Company and municipal utilities test for well over 100 contaminants each year. Many of these cannot be detected or are at trace levels, but the list below represents the major items typically found:

When disinfectants, such as Chloramine or Chlorine, meet organic matter, byproducts are created, which include:

Haloacetic Acids (HAAs) are prevalent in many of the U.S. city water supplies. San Jose does not exceed EPA standards but can exceed other proposed standards set out by the EWG for health concerns. Long-term hazards can contribute towards cancer and reproductive problems.

Hexavalent Chromium (Chromium-6) is both naturally occurring as well as an industrial contaminant and has gained fame in the Erin Brockovich movie. In San Jose groundwater, its average level is 2-4.5 ppb. It is below the former California limit but exceeds the EWG's suggested limit of 0.02 ppb. It is carcinogenic.

Click here if you want to check the tap water quality of your area .

With agricultural runoff in the valley, nitrates are closely monitored and remain within limits, though high concentrations of nitrates can be harmful to babies.

Rising issues are per- and polyfluoroalkyl substances. Low levels are being found in voluntary testing, but their persistence makes them difficult to eliminate without sophisticated filters.

Added in some regions (0.7-1.3 ppm) to help prevent tooth decay. Also found naturally in groundwater.

Trace levels of arsenic are found within EPA guidelines but above some health guidelines. Other trace elements, such as uranium or radium (radiological contaminants), have been found in some groundwater samples.

San Jose water is moderately hard (11-26 grains per gallon in groundwater-heavy mixtures), and it tends to form scales in pipes and home appliances.

Not common in source water but can leach from old plumbing in homes. Flush taps if sitting for long periods of hours.

Related article: Lead in Our Water: Risks, Realities, and Removal | Expert Opinion

Yes. Where public water is available (Evergreen, North San Jose, Alviso), fluorides are added for dental health reasons. Amounts are controlled and within safe levels following CDC recommendations.

It is moderately to very hard, perhaps producing limescale. For household purposes, a home water softener is useful.

Chloramine can create an aftertaste that doesn’t evaporate, unlike chlorine. Hardness and some DBPs can contribute.

The lead present in source water is trace, yet older homes (constructed before 1986) pose a potential for leaching. Utilities hold stockpiles of lead service lines, and most are safe.

Concentrations are low in some testing, below advisory levels, although monitoring is ongoing due to increasingly restrictive regulation.

Not really, actually, because tap water is carefully regulated and much cheaper. Bottled water has no fluoridating advantage and creates plastic pollution.

Look for Consumer Confidence Reports on San Jose Water or the City of San Jose websites on an annual basis. Utilize resources such as EWG's Tap Water Database for your zip code. For questions, please call your provider—San Jose Water stresses transparency and community outreach.

In other words, the tap water found in San Jose is an assured, regulated source that is safe for consumption. Educating oneself on its composition and the use of filtration systems within the household means that it may be consumed with renewed confidence.