Water reservoir in the foreground with trees and lake and sky in the background

Water Quality

Our Commitment to Quality

San Jose Water is committed to supplying water that meets or surpasses all state and federal drinking standards. Browse the sections below to get information on water quality topics.

In addition, you can find a summary of our most recent water testing results along with other important information in our Annual Water Quality report.

Download a copy of the 2020 report here.

Water Source Change – April 2021

Water Source Change graphic
Montevina Shutdown Impacted Area Map













SJW is fortunate to have three different sources of water: groundwater, imported water and local mountain supplies. Our distribution system switches water sources to meet demand.

Beginning Monday, April 12, we will be shutting down our Montevina Water Treatment Plant due to a lack of available local supply in the Santa Cruz Mountains. We anticipate it coming back online in Fall 2021.

With this operational change, approximately 1,400 customers in the west side of San Jose Water’s distribution system will transition from chloraminated surface water from Montevina Ultrafiltration Plant, to chlorinated groundwater.

The blending of disinfectants during the transition can cause taste and odor changes — including chemical, chlorinous or metallic aromas and flavors. Additionally, after the transition is complete in one to two weeks, customers may notice a continuing difference between surface water and groundwater.

Groundwater disinfected with free chlorine has an earthier smell. Chlorine is more readily detectable in taste and smell than chloramine. Groundwater has higher hardness, meaning you may notice white deposits, scale and spotting on dishware. We anticipate this change to last for the next several months.

Update: On April 21st, approximately 600 customers in the Saratoga, Monte Sereno, and Los Gatos area are transitioning from chloraminated surface waterimported from Valley Water to chlorinated groundwater.

Please know that both sources meet all drinking water standards and are safe to drink.

For more information on hard water, visit our Water FAQs page or call us at (408) 279-7900.

Water Source Change – December 2020

SJW has made some recent operational changes, with approximately 5,500 customers in the Saratoga area transitioning from chloraminated imported water to chlorinated groundwater.

San Jose Water employee checking water outlet


Learn more about PFAS and how SJW is addressing it.

Staff member adjusting backflow device


"Backflow" is the reversal of flow of a liquid, gas, or suspended solid into the potable water supply. Find out more about backflow and how we prevent it.

PFAS – What’s in my water?

Updated June 22, 2020

Our top priority at San Jose Water is delivering safe, high-quality and reliable water service to our customers and communities. We immediately discontinued the use of two of our wells at Malone Road Station upon discovering concentrations of perfluorooctane sulfonate (PFOS), a manmade substance widely used in consumer products from carpeting to Teflon pans. All affected customers have been notified by letter.

Water Contaminant FAQ

Read up on water contaminants and how we manage them.


What is fluoride and how does it affect your water? See answers to these questions as well as the fluoridation levels in your area.

Water Supply FAQs

Where does your water come from? Find out here.

Water Heaters

Get tips on water heater maintenance and more.

Hard & Soft Water FAQs

See what "hard" and "soft" water mean, and how to tell that either flow through your pipes.

Safety + Quality FAQs

Get answers to frequently asked questions about the quality of our water.

Water Pressure

Understand high and low water pressure, and how to manage both.

Color, Sediment, Taste & Odor FAQs

Many factors affect your water. See answers to frequently asked questions about its attributes.