B79/100
Palo Alto Tap Water Quality: Is It Safe to Drink? (2026 Report)
Serving 70,020 residents · California
What's In Palo Alto's Tap Water?
69
Contaminants Tested
0
Exceed EPA Limits
0
Above EPA Goals
EPA Violation History
No violations in the past 5 years
Full EPA compliance since 2015.
Understanding violation severity
Tier 1Urgent health risk. Utility must notify all customers within 24 hours.Tier 2Important health or treatment issue. Customers notified within 30 days.Tier 3Administrative or monitoring issue. Reported in the annual water quality report.
Source: EPA Safe Drinking Water Information System (SDWIS) · Updated quarterly
Water Utility Details
O'CONNOR TRACT CO-OPERATIVE WATER CO.
Population Served
2,789
Water Source
Groundwater
System ID
CA4110019
CITY OF PALO ALTO
Population Served
67,231
Water Source
Purchased Surface Water
System ID
CA4310009
Frequently Asked Questions About Palo Alto Water
Is Palo Alto tap water safe to drink?
Palo Alto, California tap water receives a grade of B (79/100), which is considered good. Out of 69 contaminants tested, none exceed EPA maximum contaminant levels (MCLs). While the water meets federal standards, some residents may still choose to use a filter for additional peace of mind.
What contaminants are in Palo Alto's water?
69 contaminants were tested in Palo Alto's water supply. No contaminants exceed EPA legal limits (MCLs) or health goals (MCLGs), which is a positive indicator of water quality.
Does Palo Alto have any water quality violations?
Yes, Palo Alto has 10 EPA violation(s) on record, with the most recent in 2018. Violation types include TT, MR, MCL. 8 of these are health-based violations, which are the most serious category.
Do I need a water filter in Palo Alto?
Palo Alto water meets EPA standards, so a filter is not strictly necessary. However, some residents prefer the added security of a water filter. EPA health goals (MCLGs) are stricter than legal limits and are set at levels with zero expected health risk. All contaminants are within health goals.
Where does Palo Alto's tap water come from?
Palo Alto's drinking water is sourced from groundwater and supplied by O'CONNOR TRACT CO-OPERATIVE WATER CO. and 1 other water system(s). The system serves approximately 70,020 people. Groundwater is pumped from underground aquifers, which often provides natural filtration.
How often is Palo Alto's water tested?
Under the Safe Drinking Water Act (SDWA), water utilities are required to regularly test for over 90 contaminants. Testing frequency varies by contaminant — some are tested monthly, others quarterly or annually. Palo Alto's water systems must report results to the EPA and publish an annual Consumer Confidence Report (CCR). The data on this page reflects the latest available EPA testing data.
How does Palo Alto's water compare to other cities in California?
Palo Alto's water quality score of 79/100 earns a grade of B, which is considered good. This is an above-average score compared to many cities nationwide. Visit our California state page to see how all cities in the state compare.
What should I do if I'm concerned about Palo Alto's water quality?
If you have concerns about Palo Alto's tap water, consider these steps: (1) Request your utility's annual Consumer Confidence Report for detailed local data. (2) Get your water independently tested through a state-certified laboratory. (3) Consider an NSF-certified water filter rated for the contaminants found in your area. (4) Contact your water utility (O'CONNOR TRACT CO-OPERATIVE WATER CO.) with specific questions. (5) Report water quality issues to your state drinking water program or the EPA Safe Drinking Water Hotline at 800-426-4791.