Water Quality in San Luis Obispo, CA: 2 Violations - Grade N/A
7 water systems · 5 directly mapped ZIP records
Available EPA records report 2 violations across 5 directly mapped ZIP records with known counts for San Luis Obispo. This is compliance evidence, not a property-level tap-water verdict.
Data: EPA Safe Drinking Water Information System (SDWIS)
Water Quality by ZIP Code in San Luis Obispo
This table shows typed EPA water evidence only. Missing violation counts are displayed as N/A, not zero.
| ZIP Code | Violations | Health | |
|---|---|---|---|
| 93401 | 1 | 1 | View report → |
| 93409 | 1 | 0 | View report → |
| 93405 | 0 | 0 | View report → |
| 93407 | 0 | 0 | View report → |
| 93410 | 0 | 0 | View report → |
Water Quality Overview
San Luis Obispo, California has directly mapped EPA water-system data for 5 ZIP codes. This page reports typed compliance facts and does not relabel the multi-source Home Safety Score as a drinking-water grade.
The available EPA records report 2 violations, including 1 health-based violation across 5 directly mapped ZIP records with reported counts.
Lead Levels
The average 90th percentile lead level across San Luis Obispo water systems is 0.0007 mg/L - within EPA limits. No exceedances appear among the 5 ZIP records with known lead status.
With 68% of homes built before 1986, San Luis Obispo 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 Luis Obispo
San Luis Obispo is served by 7 community water systems regulated under the Safe Drinking Water Act. These systems collectively serve approximately 63,932 people across 8 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 6 enforcement actions against water systems serving San Luis Obispo. Enforcement actions range from informal compliance assistance to formal orders and penalties.
How to Check Your Water in San Luis Obispo
Enter your ZIP code on ZipCheckup to see your specific water system data, including contaminant levels and violation history
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 Luis Obispo Water Systems
The following contaminants have been detected or caused violations across San Luis Obispo's water systems:
| Contaminant | Category | MCL | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|---|
| E. coli | Microbiological | N/A | 1 | 1 | No |
MCL = Maximum Contaminant Level (EPA enforceable standard). Health-based violations indicate levels that may pose direct health risks.
EPA Enforcement History
The EPA and state regulators have taken 6 enforcement actions against water systems serving San Luis Obispo. Recent actions:
| Date | Action Type |
|---|---|
| 2025-05-07 | State Filed Suit |
| 2025-05-05 | State Order Extension |
| 2023-07-24 | State Order Extension |
| 2023-07-06 | State Filed Suit |
| 2021-02-23 | State Order Extension |
| 2021-02-01 | State Filed Suit |
Enforcement actions range from informal compliance assistance to formal orders and penalties. The most recent action was on 2025-05-07.
San Luis Obispo vs. Nearby California Cities
How San Luis Obispo's water quality compares to similar cities in California:
| City | Direct EPA ZIPs | Violations | Systems | Population |
|---|---|---|---|---|
| San Luis Obispo | 5 | 2 | 7 | 63,932 |
| Laguna Niguel | 1 | 1 | 3 | 64,023 |
| Carmichael | 1 | 6 | 5 | 63,052 |
| Lynwood | 1 | 0 | 4 | 64,918 |
Water Quality by ZIP Code in San Luis Obispo
EPA coverage and recorded violations can differ across San Luis Obispo's ZIP codes. Missing counts are shown as unavailable, not zero:
Common Questions About San Luis Obispo Water
These are the most common questions residents search for about water quality in San Luis Obispo, California:
Is San Luis Obispo water hard or soft? Water hardness varies by source. San Luis Obispo's 7 water systems use multiple sources. Check your ZIP code report for specific hardness data.
Can I drink San Luis Obispo tap water? City-level EPA records cannot determine safety at a specific tap. The measured subset contains 1 health-based violation; check the affected utility record and consider certified testing.
What is the best water filter for San Luis Obispo? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
San Luis Obispo vs. California Average
Understanding how San Luis Obispo 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 Luis Obispo.
ZIP Codes in San Luis Obispo
San Luis Obispo spans 8 ZIP codes. EPA water-system coverage is available for 5 directly mapped ZIP codes. 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
Source reporting periods vary. See each cited source for its publication schedule.