Water Quality in San Diego, CA: 1053 Violations — Grade C
Grade C · Score 60/100 · 5 water systems · Updated 2026-05-03
San Diego'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
Looking at EPA compliance data for San Diego, CA, the record shows 1053 violations — findings that span health-based exceedances, monitoring lapses, and enforcement events tied to local utilities in the SDWIS database.
Water Quality Map: San Diego, CA
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Water Quality by ZIP Code in San Diego
Water quality varies across San Diego's 81 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 92101 | F | 35 | 13 | 4 | View report → |
| 92108 | C | 55 | 13 | 4 | View report → |
| 92109 | C | 55 | 13 | 4 | View report → |
| 92113 | C | 55 | 13 | 4 | View report → |
| 92120 | C | 55 | 13 | 4 | View report → |
| 92121 | C | 55 | 13 | 4 | View report → |
| 92102 | C | 60 | 13 | 4 | View report → |
| 92103 | C | 60 | 13 | 4 | View report → |
| 92105 | C | 60 | 13 | 4 | View report → |
| 92106 | C | 60 | 13 | 4 | View report → |
| 92107 | C | 60 | 13 | 4 | View report → |
| 92110 | C | 60 | 13 | 4 | View report → |
| 92112 | C | 60 | 13 | 4 | View report → |
| 92114 | C | 60 | 13 | 4 | View report → |
| 92115 | C | 60 | 13 | 4 | View report → |
Violation Trend
EPA violations recorded for water systems serving San Diego.
Water Quality Overview
San Diego, California receives a water quality grade of C with an overall score of 60 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
The 5 water systems serving San Diego have accumulated 1053 EPA violations, including 324 health-based violations. These violations are tracked across 81 ZIP codes serving approximately 1,422,927 people.
What Grade C Means
A grade of C indicates moderate compliance issues. San Diego'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 Diego water systems is 0.0107 mg/L — within EPA limits. No ZIP codes exceed the EPA lead action level.
With 63% of homes built before 1986, San Diego 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 San Diego
San Diego is served by 5 community water systems regulated under the Safe Drinking Water Act. These systems collectively serve approximately 1,422,927 people across 81 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 648 enforcement actions against water systems serving San Diego. Enforcement actions range from informal compliance assistance to formal orders and penalties.
How to Check Your Water in San Diego
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 Diego Water Systems
The following contaminants have been detected or caused violations across San Diego's water systems:
| Contaminant | Category | MCL | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|---|
| Total Coliform | Microbiological | N/A | 162 | 81 | No |
| Stage 2 DBP Rule | Treatment Technique | N/A | 162 | 81 | Yes |
| Stage 1 DBP Rule | Treatment Technique | N/A | 81 | 81 | 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 Diego:
| Year | Total Violations | Health-Based |
|---|---|---|
| 2022 | 243 | 243 |
| 2023 | 81 | 81 |
| 2024 | 81 | 81 |
Violations have decreased from 243 in 2022 to 81 in 2024, indicating improving compliance.
EPA Enforcement History
The EPA and state regulators have taken 8 enforcement actions against water systems serving San Diego. Recent actions:
| Date | Action Type |
|---|---|
| 2024-09-24 | State Order Extension |
| 2024-01-16 | State Order Extension |
| 2023-12-27 | State Filed Suit |
| 2023-06-21 | State Filed Suit |
| 2023-01-06 | State Filed Suit |
| 2023-01-06 | State Order Extension |
| 2022-10-05 | State Filed Suit |
| 2022-09-26 | State Order Extension |
Enforcement actions range from informal compliance assistance to formal orders and penalties. The most recent action was on 2024-09-24.
San Diego vs. Nearby California Cities
How San Diego's water quality compares to similar cities in California:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| San Diego | C | 1053 | 5 | 1,422,927 |
| Alameda | C | 0 | 1 | 1,442,800 |
| Albany | C | 0 | 1 | 1,442,800 |
| Berkeley | C | 0 | 1 | 1,442,800 |
Recommended Water Filters for San Diego
Based on contaminants detected in San Diego's water supply, these filter types are recommended:
Reverse Osmosis (under-sink)
- Removes: Copper
- Effectiveness: 95-99%
- Cost range: $150–$500
- Certification: NSF/ANSI 58
- Recommended products:
Granular Activated Carbon (GAC, whole-house POE)
- Removes: Total Trihalomethanes (TTHM)
- Effectiveness: 80-99%
- Cost range: $400–$2000
- Certification: NSF/ANSI 53
- Recommended products:
Water Quality by ZIP Code in San Diego
Water quality varies across San Diego's ZIP codes. The table below shows the worst-scoring and best-scoring areas:
| ZIP Code | Score | Grade | Violations | Health-Based |
|---|---|---|---|---|
| 92101 | 35 | F | 13 | 4 |
| 92108 | 55 | C | 13 | 4 |
| 92109 | 55 | C | 13 | 4 |
| 92113 | 55 | C | 13 | 4 |
| 92120 | 55 | C | 13 | 4 |
| 92121 | 55 | C | 13 | 4 |
| 92102 | 60 | C | 13 | 4 |
| 92103 | 60 | C | 13 | 4 |
| 92105 | 60 | C | 13 | 4 |
| 92106 | 60 | C | 13 | 4 |
| 92139 | 65 | C | 13 | 4 |
| 92131 | 65 | C | 13 | 4 |
| 92130 | 65 | C | 13 | 4 |
| 92129 | 65 | C | 13 | 4 |
| 92128 | 65 | C | 13 | 4 |
Water quality scores in San Diego range from 35 to 65 — a spread of 30 points. This variation means your specific ZIP code matters significantly.
Common Questions About San Diego Water
These are the most common questions residents search for about water quality in San Diego, California:
Is San Diego water hard or soft? Water hardness varies by source. San Diego's 5 water systems use multiple sources. Check your ZIP code report for specific hardness data.
Can I drink San Diego tap water? San Diego's water receives a grade of C (60/100). There are 324 health-based violations — consider filtration.
What is the best water filter for San Diego? Based on detected contaminants, a reverse osmosis (under-sink) filter is most recommended. See our Water Filter Matcher for personalized recommendations.
San Diego vs. California Average
Understanding how San Diego 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 Diego.
ZIP Codes in San Diego
San Diego spans 81 ZIP codes. The ZIP with the lowest water quality score is 92101. 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.