Water Quality in San Francisco, CA: 420 Violations — Grade C
Grade C · Score 55/100 · 4 water systems · Updated 2026-05-03
San Francisco's water has moderate compliance issues. Residents in affected areas should consider filtration.
Data: EPA Safe Drinking Water Information System (SDWIS) Last verified: 2026-05-03
EPA files for San Francisco, CA document 420 water violations — a record that encompasses health-based exceedances, monitoring and reporting failures, and any other compliance events registered for local public water systems across all available federal compliance records for this area.
Water Quality Map: San Francisco, CA
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Water Quality by ZIP Code in San Francisco
Water quality varies across San Francisco's 60 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 94101 | D | 53 | 7 | 6 | View report → |
| 94117 | D | 53 | 7 | 6 | View report → |
| 94119 | D | 53 | 7 | 6 | View report → |
| 94125 | D | 53 | 7 | 6 | View report → |
| 94126 | D | 53 | 7 | 6 | View report → |
| 94128 | D | 53 | 7 | 6 | View report → |
| 94129 | D | 53 | 7 | 6 | View report → |
| 94130 | D | 53 | 7 | 6 | View report → |
| 94134 | D | 53 | 7 | 6 | View report → |
| 94136 | D | 53 | 7 | 6 | View report → |
| 94137 | D | 53 | 7 | 6 | View report → |
| 94139 | D | 53 | 7 | 6 | View report → |
| 94140 | D | 53 | 7 | 6 | View report → |
| 94141 | D | 53 | 7 | 6 | View report → |
| 94142 | D | 53 | 7 | 6 | View report → |
Violation Trend
EPA violations recorded for water systems serving San Francisco.
Water Quality Overview
San Francisco, California receives a water quality grade of C with an overall score of 55 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
The 4 water systems serving San Francisco have accumulated 420 EPA violations, including 360 health-based violations. These violations are tracked across 60 ZIP codes serving approximately 3,643 people.
What Grade C Means
A grade of C indicates moderate compliance issues. San Francisco's water systems have some violations that warrant attention. While the water may still be safe for most people, residents in affected ZIP codes should consider additional testing or filtration.
Lead Levels
The average 90th percentile lead level across San Francisco water systems is 0.0030 mg/L — within EPA limits. No ZIP codes exceed the EPA lead action level.
With 79% of homes built before 1986, San Francisco 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.
Radon Risk
San Francisco is in EPA Radon Zone 2 (Moderate risk). Testing is recommended, especially for homes with basements or ground-level living spaces.
Water Systems Serving San Francisco
San Francisco is served by 4 community water systems regulated under the Safe Drinking Water Act. These systems collectively serve approximately 3,643 people across 60 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
The EPA has taken 240 enforcement actions against water systems serving San Francisco. Enforcement actions range from informal compliance assistance to formal orders and penalties.
How to Check Your Water in San Francisco
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
Contaminants Detected in San Francisco Water Systems
The following contaminants have been detected or caused violations across San Francisco's water systems:
| Contaminant | Category | MCL | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|---|
| Lead | Inorganic | 0.015 mg/L | 60 | 60 | No |
MCL = Maximum Contaminant Level (EPA enforceable standard). Health-based violations indicate levels that may pose direct health risks.
Violation Trend Over Time
Year-by-year EPA violations recorded for water systems serving San Francisco:
| Year | Total Violations | Health-Based |
|---|---|---|
| 2021 | 60 | 60 |
| 2022 | 180 | 180 |
| 2024 | 120 | 120 |
Violations have increased from 60 in 2021 to 120 in 2024. This trend warrants monitoring.
EPA Enforcement History
The EPA and state regulators have taken 4 enforcement actions against water systems serving San Francisco. Recent actions:
| Date | Action Type |
|---|---|
| 2024-03-08 | State Order Extension |
| 2023-02-09 | State Filed Suit |
| 2022-03-11 | State Filed Suit |
| 2022-01-07 | State Filed Suit |
Enforcement actions range from informal compliance assistance to formal orders and penalties. The most recent action was on 2024-03-08.
San Francisco vs. Nearby California Cities
How San Francisco's water quality compares to similar cities in California:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| San Francisco | C | 420 | 4 | 3,643 |
| Mount Shasta | A | 2 | 1 | 3,642 |
| Aptos | B | 0 | 5 | 3,686 |
| Mariposa | B | 1 | 5 | 3,695 |
Water Quality by ZIP Code in San Francisco
Water quality varies across San Francisco's ZIP codes. The table below shows the worst-scoring and best-scoring areas:
| ZIP Code | Score | Grade | Violations | Health-Based |
|---|---|---|---|---|
| 94101 | 53 | D | 7 | 6 |
| 94117 | 53 | D | 7 | 6 |
| 94119 | 53 | D | 7 | 6 |
| 94125 | 53 | D | 7 | 6 |
| 94126 | 53 | D | 7 | 6 |
| 94128 | 53 | D | 7 | 6 |
| 94129 | 53 | D | 7 | 6 |
| 94130 | 53 | D | 7 | 6 |
| 94134 | 53 | D | 7 | 6 |
| 94136 | 53 | D | 7 | 6 |
| 94133 | 59 | C | 7 | 6 |
| 94132 | 59 | C | 7 | 6 |
| 94131 | 59 | C | 7 | 6 |
| 94127 | 59 | C | 7 | 6 |
| 94124 | 59 | C | 7 | 6 |
Common Questions About San Francisco Water
These are the most common questions residents search for about water quality in San Francisco, California:
Is San Francisco water hard or soft? Water hardness varies by source. San Francisco's 4 water systems use multiple sources. Check your ZIP code report for specific hardness data.
Can I drink San Francisco tap water? San Francisco's water receives a grade of C (55/100). There are 360 health-based violations — consider filtration.
What is the best water filter for San Francisco? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
San Francisco vs. California Average
Understanding how San Francisco 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 San Francisco.
ZIP Codes in San Francisco
San Francisco spans 60 ZIP codes. The ZIP with the lowest water quality score is 94101. 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.