Water Quality in Cotati, CA: No Violations — Grade A
Grade A · Score 95/100 · 2 water systems · Updated 2026-05-03
Cotati's water meets all EPA standards with no health-based violations.
Data: EPA Safe Drinking Water Information System (SDWIS) Last verified: 2026-05-03
A clean federal EPA record is what the data shows for Cotati, CA — 2 systems tracked across the full available compliance history, with no MCL exceedances, no unresolved monitoring gaps, and no enforcement proceedings documented at any stage.
Water Quality by ZIP Code in Cotati
Water quality varies across Cotati's 1 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 94931 | A | 95 | 0 | 0 | View report → |
Water Quality Overview
Cotati, California receives a water quality grade of A with an overall score of 95 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
No EPA violations have been recorded for the 2 water systems serving Cotati. This is a positive indicator, though it does not guarantee the absence of all contaminants — some substances (like PFAS) are not yet fully regulated.
What Grade A Means
A grade of A indicates excellent compliance with EPA drinking water standards. Cotati's water systems have maintained strong performance in both contaminant monitoring and regulatory compliance.
Lead Levels
The average 90th percentile lead level across Cotati water systems is 0.0048 mg/L — within EPA limits. No ZIP codes exceed the EPA lead action level.
With 63% of homes built before 1986, Cotati has a higher-than-average risk of lead from older plumbing. Lead solder was banned in 1986, and homes built before this date may have lead in pipes, solder joints, or fixtures.
Water Systems Serving Cotati
Cotati is served by 2 community water systems regulated under the Safe Drinking Water Act. These systems collectively serve approximately 7,379 people across 1 ZIP codes.
Each water system is identified by a Public Water System ID (PWSID) and is required to:
- Test for over 90 regulated contaminants on a regular schedule
- Report results to the EPA and state regulators
- Issue an annual Consumer Confidence Report (CCR) to all customers
- Take corrective action when violations occur
How to Check Your Water in Cotati
Enter your ZIP code on ZipCheckup to see your specific water system data, including contaminant levels, violation history, and safety scores
Request your CCR — your water utility must provide an annual Consumer Confidence Report with detailed test results for all monitored contaminants
Get a home test — certified kits cost $20–$50 and test for lead, bacteria, and common contaminants. Professional lab tests ($150–$400) cover a broader panel
Consider filtration — NSF-certified filters can remove specific contaminants. Reverse osmosis removes the broadest range; activated carbon is effective for chlorine and many organics
Check for advisories — monitor your local utility website and local news for boil water advisories or system alerts
Cotati vs. Nearby California Cities
How Cotati's water quality compares to similar cities in California:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| Cotati | A | 0 | 2 | 7,379 |
| Tahoe Vista | B | 0 | 3 | 7,352 |
| Escalon | A | 0 | 1 | 7,429 |
| Dos Palos | C | 16 | 1 | 7,452 |
Common Questions About Cotati Water
These are the most common questions residents search for about water quality in Cotati, California:
Is Cotati water hard or soft? Water hardness varies by source. Cotati's 2 water systems use multiple sources. Check your ZIP code report for specific hardness data.
Can I drink Cotati tap water? Cotati's water receives a grade of A (95/100). No health-based violations have been recorded, but home testing is always recommended.
What is the best water filter for Cotati? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
Cotati vs. California Average
Understanding how Cotati compares to the broader California average helps contextualize your local water quality. Factors like water source, treatment methods, and infrastructure age all contribute to differences between cities in the same state.
To see how individual neighborhoods compare, check the ZIP code reports below — water quality can vary significantly even within Cotati.
ZIP Codes in Cotati
Cotati spans 1 ZIP code. Each ZIP code has its own water quality profile based on the specific water system serving that area. Check each ZIP code for detailed contaminant data, violation history, and system information.
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Radon: EPA Map of Radon Zones
- Enforcement: EPA ECHO database
- Filter recommendations: NSF/ANSI certified products
Updated daily.
Frequently Asked Questions
Your Water is Safe — Here's How to Keep It That Way
Grade A is excellent news. Here's what proactive homeowners do to maintain water quality:
Annual Water Testing
EPA recommends annual testing even with clean water. Home test kits: $20-$50. Catches changes before they become problems.
Maintenance Filtration
A basic carbon filter removes chlorine taste and catches emerging contaminants like PFAS that aren't yet fully regulated.
Plumbing Check
Even safe city water picks up lead from home pipes. If your home was built before 1986, a one-time pipe inspection is recommended.