Water Quality in Lancaster, CA: 144 Violations — Grade D
Grade D · Score 40/100 · 5 water systems · Updated 2026-05-03
Lancaster's water has significant violations. Water testing and filtration are recommended.
Data: EPA Safe Drinking Water Information System (SDWIS) Last verified: 2026-05-03
On record with EPA: Lancaster, CA has 144 water violations.
Water Quality Map: Lancaster, CA
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Water Quality by ZIP Code in Lancaster
Water quality varies across Lancaster's 6 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 93539 | F | 36 | 24 | 19 | View report → |
| 93584 | F | 36 | 24 | 19 | View report → |
| 93586 | F | 36 | 24 | 19 | View report → |
| 93535 | D | 43 | 24 | 19 | View report → |
| 93536 | D | 43 | 24 | 19 | View report → |
| 93534 | D | 48 | 24 | 19 | View report → |
Violation Trend
EPA violations recorded for water systems serving Lancaster.
Water Quality Overview
Lancaster, California receives a water quality grade of D with an overall score of 40 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
The 5 water systems serving Lancaster have accumulated 144 EPA violations, including 114 health-based violations. These violations are tracked across 6 ZIP codes serving approximately 6,172 people.
What Grade D Means
A grade of D indicates significant compliance issues. Lancaster's water systems have accumulated violations that suggest ongoing water quality challenges. Residents should check their specific ZIP code report and consider water testing or filtration.
Lead Levels
The average 90th percentile lead level across Lancaster water systems is 0.0092 mg/L — within EPA limits. No ZIP codes exceed the EPA lead action level.
With 56% of homes built before 1986, Lancaster 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
Lancaster is in EPA Radon Zone 2 (Moderate risk). Testing is recommended, especially for homes with basements or ground-level living spaces.
Water Systems Serving Lancaster
Lancaster is served by 5 community water systems regulated under the Safe Drinking Water Act. These systems collectively serve approximately 6,172 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 60 enforcement actions against water systems serving Lancaster. Enforcement actions range from informal compliance assistance to formal orders and penalties.
How to Check Your Water in Lancaster
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 Lancaster Water Systems
The following contaminants have been detected or caused violations across Lancaster's water systems:
| Contaminant | Category | MCL | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|---|
| Barium | Inorganic | 2 mg/L | 108 | 6 | Yes |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 0.08 mg/L | 12 | 6 | No |
| Revised Total Coliform Rule | Microbiological | N/A | 6 | 6 | Yes |
| Total Coliform | Microbiological | N/A | 6 | 6 | No |
| Stage 1 DBP 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.
Violation Trend Over Time
Year-by-year EPA violations recorded for water systems serving Lancaster:
| Year | Total Violations | Health-Based |
|---|---|---|
| 2022 | 30 | 24 |
| 2023 | 24 | 24 |
| 2024 | 24 | 24 |
| 2025 | 12 | 12 |
Violations have decreased from 30 in 2022 to 12 in 2025, indicating improving compliance.
EPA Enforcement History
The EPA and state regulators have taken 10 enforcement actions against water systems serving Lancaster. Recent actions:
| Date | Action Type |
|---|---|
| 2025-07-24 | State Filed Suit |
| 2024-07-01 | State Order Extension |
| 2023-09-05 | EPA Formal Action |
| 2023-08-01 | State Order Extension |
| 2023-02-01 | State Filed Suit |
| 2023-01-27 | State Filed Suit |
| 2023-01-11 | State Filed Suit |
| 2022-11-16 | State Order Extension |
| 2022-08-01 | State Order Extension |
| 2022-06-15 | State Order Extension |
Enforcement actions range from informal compliance assistance to formal orders and penalties. The most recent action was on 2025-07-24.
Lancaster vs. Nearby California Cities
How Lancaster's water quality compares to similar cities in California:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| Lancaster | D | 144 | 5 | 6,172 |
| Coarsegold | C | 15 | 4 | 6,160 |
| Cutler | C | 6 | 1 | 6,200 |
| Yettem | D | 0 | 1 | 6,200 |
Water Quality by ZIP Code in Lancaster
Water quality varies across Lancaster's ZIP codes. The table below shows the worst-scoring and best-scoring areas:
| ZIP Code | Score | Grade | Violations | Health-Based |
|---|---|---|---|---|
| 93539 | 36 | F | 24 | 19 |
| 93584 | 36 | F | 24 | 19 |
| 93586 | 36 | F | 24 | 19 |
| 93535 | 43 | D | 24 | 19 |
| 93536 | 43 | D | 24 | 19 |
| 93534 | 48 | D | 24 | 19 |
Common Questions About Lancaster Water
These are the most common questions residents search for about water quality in Lancaster, California:
Is Lancaster water hard or soft? Water hardness varies by source. Lancaster's 5 water systems use multiple sources. Check your ZIP code report for specific hardness data.
Can I drink Lancaster tap water? Lancaster's water receives a grade of D (40/100). There are 114 health-based violations — consider filtration.
What is the best water filter for Lancaster? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
Lancaster vs. California Average
Understanding how Lancaster 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 Lancaster.
ZIP Codes in Lancaster
Lancaster spans 6 ZIP codes. The ZIP with the lowest water quality score is 93534. 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.