Water Quality in Simi Valley, CA: 18 Violations — Grade B
Grade B · Score 77/100 · 3 water systems · Updated 2026-05-03
Simi Valley's water is mostly safe. Minor violations exist but are primarily monitoring-related.
Data: EPA Safe Drinking Water Information System (SDWIS) Last verified: 2026-05-03
EPA monitoring has flagged 18 reportable events for water systems in Simi Valley, CA.
Water Quality Map: Simi Valley, CA
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Water Quality by ZIP Code in Simi Valley
Water quality varies across Simi Valley's 6 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 93065 | C | 56 | 3 | 0 | View report → |
| 93063 | C | 61 | 3 | 0 | View report → |
| 93062 | C | 62 | 3 | 0 | View report → |
| 93093 | C | 62 | 3 | 0 | View report → |
| 93094 | C | 62 | 3 | 0 | View report → |
| 93099 | C | 62 | 3 | 0 | View report → |
Water Quality Overview
Simi Valley, California receives a water quality grade of B with an overall score of 77 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
The 3 water systems serving Simi Valley have accumulated 18 EPA violations (all monitoring/reporting type). These violations are tracked across 6 ZIP codes serving approximately 95,529 people.
What Grade B Means
A grade of B indicates good compliance with EPA drinking water standards. While not perfect, Simi Valley's water systems meet the vast majority of federal requirements. Minor violations may exist but typically relate to monitoring or reporting rather than health-based standards.
Lead Levels
The average 90th percentile lead level across Simi Valley water systems is 0.0012 mg/L — within EPA limits. No ZIP codes exceed the EPA lead action level.
With 66% of homes built before 1986, Simi Valley 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
Simi Valley is in EPA Radon Zone 2 (Moderate risk). Testing is recommended, especially for homes with basements or ground-level living spaces.
Water Systems Serving Simi Valley
Simi Valley is served by 3 community water systems regulated under the Safe Drinking Water Act. These systems collectively serve approximately 95,529 people across 6 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 24 enforcement actions against water systems serving Simi Valley. Enforcement actions range from informal compliance assistance to formal orders and penalties.
How to Check Your Water in Simi Valley
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 Simi Valley Water Systems
The following contaminants have been detected or caused violations across Simi Valley's water systems:
| Contaminant | Category | MCL | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|---|
| Lead | Inorganic | 0.015 mg/L | 6 | 6 | No |
| Surface Water Treatment Rule | Treatment Technique | N/A | 6 | 6 | 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 4 enforcement actions against water systems serving Simi Valley. Recent actions:
| Date | Action Type |
|---|---|
| 2024-11-19 | State Filed Suit |
| 2023-12-28 | State Order Extension |
| 2023-12-15 | State Filed Suit |
| 2023-03-27 | State Filed Suit |
Enforcement actions range from informal compliance assistance to formal orders and penalties. The most recent action was on 2024-11-19.
Simi Valley vs. Nearby California Cities
How Simi Valley's water quality compares to similar cities in California:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| Simi Valley | B | 18 | 3 | 95,529 |
| Carlsbad | A | 0 | 2 | 95,158 |
| Santa Cruz | C | 54 | 5 | 95,967 |
| Brandeis | D | 0 | 1 | 94,738 |
Water Quality by ZIP Code in Simi Valley
Water quality varies across Simi Valley's ZIP codes. The table below shows the worst-scoring and best-scoring areas:
| ZIP Code | Score | Grade | Violations | Health-Based |
|---|---|---|---|---|
| 93065 | 56 | C | 3 | 0 |
| 93063 | 61 | C | 3 | 0 |
| 93062 | 62 | C | 3 | 0 |
| 93093 | 62 | C | 3 | 0 |
| 93094 | 62 | C | 3 | 0 |
| 93099 | 62 | C | 3 | 0 |
Common Questions About Simi Valley Water
These are the most common questions residents search for about water quality in Simi Valley, California:
Is Simi Valley water hard or soft? Water hardness varies by source. Simi Valley's 3 water systems use multiple sources. Check your ZIP code report for specific hardness data.
Can I drink Simi Valley tap water? Simi Valley's water receives a grade of B (77/100). No health-based violations have been recorded, but home testing is always recommended.
What is the best water filter for Simi Valley? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
Simi Valley vs. California Average
Understanding how Simi Valley 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 Simi Valley.
ZIP Codes in Simi Valley
Simi Valley spans 6 ZIP codes. The ZIP with the lowest water quality score is 93062. 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 B 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.