Water Quality in Arnold, CA: No Violations — Grade C
Grade C · Score 58/100 · 2 water systems · Updated 2026-05-03
Arnold'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
A clean federal EPA record is what the data shows for Arnold, CA — 2 systems tracked across the full available compliance history, with no MCL exceedances, no unresolved monitoring gaps, and no enforcement proceedings documented at any stage.
Water Quality by ZIP Code in Arnold
Water quality varies across Arnold's 1 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 95223 | C | 58 | 0 | 0 | View report → |
Water Quality Overview
Arnold, California receives a water quality grade of C with an overall score of 58 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
No EPA violations have been recorded for the 2 water systems serving Arnold. 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. Arnold'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 Arnold water systems is 0.0150 mg/L — within EPA limits. No ZIP codes exceed the EPA lead action level.
With 60% of homes built before 1986, Arnold 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
Arnold is in EPA Radon Zone 2 (Moderate risk). Testing is recommended, especially for homes with basements or ground-level living spaces.
Water Systems Serving Arnold
Arnold is served by 2 community water systems regulated under the Safe Drinking Water Act. These systems collectively serve approximately 5,527 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
The EPA has taken 1 enforcement action against water systems serving Arnold. Enforcement actions range from informal compliance assistance to formal orders and penalties.
How to Check Your Water in Arnold
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
EPA Enforcement History
The EPA and state regulators have taken 1 enforcement action against water systems serving Arnold. Recent actions:
| Date | Action Type |
|---|---|
| 2021-05-13 | State Order Extension |
Enforcement actions range from informal compliance assistance to formal orders and penalties. The most recent action was on 2021-05-13.
Arnold vs. Nearby California Cities
How Arnold's water quality compares to similar cities in California:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| Arnold | C | 0 | 2 | 5,527 |
| Cambria | B | 1 | 1 | 5,532 |
| Hilmar | A | 0 | 1 | 5,504 |
| Stevinson | C | 0 | 1 | 5,504 |
Common Questions About Arnold Water
These are the most common questions residents search for about water quality in Arnold, California:
Is Arnold water hard or soft? Water hardness varies by source. Arnold's 2 water systems use multiple sources. Check your ZIP code report for specific hardness data.
Can I drink Arnold tap water? Arnold's water receives a grade of C (58/100). No health-based violations have been recorded, but home testing is always recommended.
What is the best water filter for Arnold? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
Arnold vs. California Average
Understanding how Arnold 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 Arnold.
ZIP Codes in Arnold
Arnold spans 1 ZIP code. 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.