Water Quality in Mountain Pass, CA: 2 Violations — Grade B
Grade B · Score 78/100 · 1 water system · Updated 2026-05-03
Mountain Pass'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
Federal EPA data for Mountain Pass, CA shows 2 water compliance events in the record — the table below identifies system names and violation types.
Water Quality by ZIP Code in Mountain Pass
Water quality varies across Mountain Pass's 1 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 92366 | B | 78 | 2 | 1 | View report → |
Water Quality Overview
Mountain Pass, California receives a water quality grade of B with an overall score of 78 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
The 1 water system serving Mountain Pass have accumulated 2 EPA violations, including 1 health-based violation. These violations are tracked across 1 ZIP codes serving approximately 626 people.
What Grade B Means
A grade of B indicates good compliance with EPA drinking water standards. While not perfect, Mountain Pass'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 Mountain Pass water systems is 0.0009 mg/L — within EPA limits. No ZIP codes exceed the EPA lead action level.
Radon Risk
Mountain Pass is in EPA Radon Zone 2 (Moderate risk). Testing is recommended, especially for homes with basements or ground-level living spaces.
Water Systems Serving Mountain Pass
Mountain Pass is served by 1 community water system regulated under the Safe Drinking Water Act. These systems collectively serve approximately 626 people across 1 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 Mountain Pass
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 Mountain Pass Water Systems
The following contaminants have been detected or caused violations across Mountain Pass's water systems:
| Contaminant | Category | MCL | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|---|
| Stage 2 DBP Rule | Treatment Technique | N/A | 2 | 1 | Yes |
MCL = Maximum Contaminant Level (EPA enforceable standard). Health-based violations indicate levels that may pose direct health risks.
Mountain Pass vs. Nearby California Cities
How Mountain Pass's water quality compares to similar cities in California:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| Mountain Pass | B | 2 | 1 | 626 |
| Cima | D | 0 | 1 | 626 |
| Nipton | D | 0 | 1 | 626 |
| Isleton | B | 5 | 5 | 625 |
Common Questions About Mountain Pass Water
These are the most common questions residents search for about water quality in Mountain Pass, California:
Is Mountain Pass water hard or soft? Water hardness varies by source. Mountain Pass's 1 water system uses a single source. Check your ZIP code report for specific hardness data.
Can I drink Mountain Pass tap water? Mountain Pass's water receives a grade of B (78/100). There are 1 health-based violations — consider filtration.
What is the best water filter for Mountain Pass? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
Mountain Pass vs. California Average
Understanding how Mountain Pass 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 Mountain Pass.
ZIP Codes in Mountain Pass
Mountain Pass spans 1 ZIP code. The ZIP with the lowest water quality score is 92366. 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.