Water Quality in San Leandro, CA: No Violations — Grade C
Grade C · Score 68/100 · 1 water system · Updated 2026-05-03
San Leandro'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
Not one violation appears in CA's EPA file for San Leandro — 1 monitored system, all clear.
Water Quality by ZIP Code in San Leandro
Water quality varies across San Leandro's 3 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 94579 | D | 53 | 0 | 0 | View report → |
| 94577 | C | 58 | 0 | 0 | View report → |
| 94578 | C | 58 | 0 | 0 | View report → |
Water Quality Overview
San Leandro, California receives a water quality grade of C with an overall score of 68 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
No EPA violations have been recorded for the 1 water system serving San Leandro. 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 C Means
A grade of C indicates moderate compliance issues. San Leandro'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 Leandro water systems is 0.1600 mg/L — this exceeds the EPA action level of 0.015 mg/L. 3 ZIP codes exceed the EPA lead action level.
With 84% of homes built before 1986, San Leandro 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 Leandro
San Leandro is served by 1 community water system regulated under the Safe Drinking Water Act. These systems collectively serve approximately 420 people across 3 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 San Leandro
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
San Leandro vs. Nearby California Cities
How San Leandro's water quality compares to similar cities in California:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| San Leandro | C | 0 | 1 | 420 |
| San Lorenzo | B | 0 | 1 | 420 |
| Mendocino | A | 5 | 5 | 423 |
| Death Valley | B | 2 | 3 | 413 |
Water Quality by ZIP Code in San Leandro
Water quality varies across San Leandro's ZIP codes. The table below shows the worst-scoring and best-scoring areas:
Common Questions About San Leandro Water
These are the most common questions residents search for about water quality in San Leandro, California:
Is San Leandro water hard or soft? Water hardness varies by source. San Leandro's 1 water system uses a single source. Check your ZIP code report for specific hardness data.
Can I drink San Leandro tap water? San Leandro's water receives a grade of C (68/100). No health-based violations have been recorded, but home testing is always recommended.
What is the best water filter for San Leandro? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
San Leandro vs. California Average
Understanding how San Leandro 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 Leandro.
ZIP Codes in San Leandro
San Leandro spans 3 ZIP codes. 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.