Problems We Found With San Jose's Drinking Water – Hydroviv

Problems We Found With San Jose's Drinking Water


Analies Dyjak | Policy Nerd   

For Hydroviv’s assessment of San Jose drinking water, we collected water quality test data from the San Jose Water and the U.S. Environmental Protection Agency. We cross reference San Jose’s water quality data with toxicity studies in scientific and medical literature. The water filters that we sell at Hydroviv are optimized to filter out contaminants that are found in San Jose’s drinking water.

Where Does San Jose Source Its Drinking Water?

40% of San Jose’s water supply comes from 100 groundwater wells in the Santa Clara Groundwater Basin. Imported surface water accounts for 50% of the total water supply. Surface water is sourced from the Sacramento-San Joaquin Delta and is treated by the Santa Clara Water District. The remaining water is sourced from the Santa Cruz Mountains and is treated at two water treatment facilities in San Jose.

Chromium 6 In San Jose's Drinking Water 

Chromium 6 is a highly toxic metal that is currently unregulated by the EPA. In recent years, San Jose has had a major problem with this dangerous contaminant. Chromium 6 pollution is associated with metal processing, tannery facilities, chromate production, stainless steel welding, and pigment production. The 2017 water quality report for San Jose found levels of Chromium 6 as high as 6.6 parts per billion in certain groundwater sources, which is 330 times higher than the California Health Goal of 0.02 parts per billion. Chromium 6 concentrations were higher in groundwater sources surface water, which is consistent with typical point source exposure routes. Concentrations averaged 2.73 parts per billion in groundwater and 1.03 parts per billion in surface water. The state of California set their own health advisory level because Chromium 6 is not regulated by the federal government. EPA has acknowledged that Chromium 6 is a known human carcinogen through inhalation, but is still determining its cancer potential through ingestion of drinking water. Lung, nasal and sinus cancers are associated with Chromium 6 exposure. Ingestion of extremely high doses of chromium 6 compounds can cause acute respiratory, cardiovascular, gastrointestinal, hematological, hepatic, renal, and neurological distress which may result in death. If you live in San Jose, we recommend purchasing a filter optimized to remove Chromium 6, especially if you use a private well for drinking water.

Arsenic In San Jose's Drinking Water

Arsenic levels reported in the 2017 water quality report were in exceedance with the California Health Goal of 0.004 parts per billion. One of San Jose’s groundwater aquifers detected Arsenic concentrations of 2.1 parts per billion. Arsenic is a toxic substance that is linked to a long list of health problems in humans. For example, arsenic can cause a number of different cancers (e.g. skin, bladder, lung, liver, prostate), as well as create non-cancerous problems with cardiovascular (heart/blood vessels), pulmonary (lungs), immune, neurological (brain), and endocrine (e.g. diabetes) systems. Arsenic naturally occurs in bedrock, and is not the result of industrial pollution like Chromium 6.

Disinfection Byproducts (DBPs) In San Jose's Drinking Water 

San Jose’s municipal water was in also in exceedance of loose EPA standards for Disinfection Byproducts or DBPs. Concentrations were detected as high as 62 parts per billion, which exceeds EPA’s Maximum Contaminant Level of 60 parts per billion for Haloacetic Acids-5. Disinfection Byproducts are a category of emerging contaminants which means they have been detected in drinking water but the risk to human health is unknown. DBPs are formed when chlorine or chloramine-based disinfectants are routinely added to the water supply to kill bacteria. DBPs are split into two categories: Total Trihalomethanes (THMs) and Haloacetic Acids-5 (HAA5). Regulatory agencies have very little knowledge about the adverse health effects of DBPs, and their toxicity. EPA has stated that they have been linked to increased risk of bladder cancer, as well as kidney, liver, and central nervous system problems. Some disinfection byproducts have almost no toxicity, but others have been associated with cancer, reproductive problems, and developmental issues in laboratory animals. 200 million people in the United States use chlorinated tap water as their primary drinking source, so we take understanding their full health effects very seriously, even if federal agencies fail to regulate all categories.

If you’re interested in learning more about water filters that have been optimized for San Jose's tap water quality, feel free to visit to talk to a Water Nerd on our live chat feature or send us an email at

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  • Analies Dyjak