San Jose Drinking Water Quality
What's Really in Your Tap Water?
San Jose tap water is generally safe, though there are a few things worth knowing. At 190.5 ppm (11.1 gpg), the water is quite hard — you may notice mineral buildup on fixtures. Lead levels test well below the EPA action level. Only 2 minor violations in the past 3 years.
Generally Safe
Minor compliance issues
11.1 GPG hardness
Lead
Below EPA action level
EPA action level: 15 ppb
Hardness
Very Hard water
US Average: 100 ppm
Is San Jose Tap Water Safe to Drink?
San Jose tap water is generally safe with minor compliance issues.
- •2 health-based violations in the past 3 years across 4 water systems.
- •Consider testing your water at home for complete peace of mind.
The data below shows test results from 4 water utilities serving 1.2M people in the San Jose area. Water quality testing is conducted regularly and reported to the EPA.
How Hard is San Jose Water?
190.5 ppm
11.1 grains per gallon
Very hard water causes significant mineral buildup. A water softener is recommended.
Impact on Your Home
Shower
Dries out skin & hair
Kitchen
Heavy mineral deposits
Laundry
Stiff, dingy clothes
Appliances
Significant scale
Regional Comparison
Values in ppm (mg/L as CaCO₃)
Based on 58 water samples from Santa Clara County.
Your pipes tell a different story
The data above shows what leaves the treatment plant—not what comes out of your faucet. Old pipes, lead solder, and building plumbing can add contaminants the city never tests for. Know exactly what's in your San Jose tap water.
Home test kits detect lead, bacteria, pesticides, and 100+ other contaminants. Results in 5-10 business days from certified labs.
Lead & Contaminants
Understanding lead levels and water quality violations in San Jose
Lead Test Results
90th Percentile Lead Level
2.85 ppb
San Jose lead levels are well within safe limits.
Regular testing is still recommended, as lead can enter water through household plumbing.
Last sampled: 2025-12-31
About Lead in Drinking Water
What is Lead in Water?
Lead is a toxic metal that can dissolve into drinking water from older pipes, solder, and fixtures. It's invisible, tasteless, and odorless, making testing the only way to detect it. The EPA has set an action level of 15 ppb, though they emphasize there is no safe level of lead exposure.
Potential Health Effects
Developmental delays, learning difficulties, lower IQ, behavioral issues
High blood pressure, kidney damage, reproductive issues
How to Reduce Exposure
- •Run water for 30 seconds to 2 minutes before drinking, especially in the morning
- •Use cold water for cooking and drinking (hot water dissolves more lead)
- •Install a NSF-certified filter designed to remove lead
- •Test your water, especially if your home was built before 1986
EPA Compliance History
Action Recommended
Active health-based violations detectedConsider using a certified water filter until violations are resolved. Contact your utility for updates on corrective actions.
3-Year Violation Summary
2
Total Violations
2
Health-Related
0
Administrative
Health-Related Violations
Contaminant exceeded EPA safety limits. May require filter or alternative water source.
Administrative Violations
Missed testing deadlines or reporting. Does not indicate water quality issues.
Who Provides San Jose's Water?
Utility Name
SAN JOSE WATER
EPA System ID (PWSID)
CA4310011
Primary Water Source
Surface Water
Population Served
1.2M
Frequently Asked Questions
Common questions about San Jose tap water quality
Nearby Cities in California
Los Angeles
Hard water
East Bay
Very Hard water
San Diego
Very Hard water
California
Hard water
Eastern Municipal Wd
Very Hard water
Fresno
Moderate water
This data is for informational purposes only. Water quality can vary by neighborhood and building. For official reports, contact your local water utility or the EPA. Learn about our methodology