Water Quality in Rialto, CA: No Violations — Grade B
Grade B · Score 75/100 · 2 water systems · Updated 2026-05-03
Rialto'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
No EPA violations have been identified for Rialto, CA — 2 systems, all within federal limits.
Water Quality by ZIP Code in Rialto
Water quality varies across Rialto's 2 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 92376 | B | 75 | 0 | 0 | View report → |
| 92377 | B | 75 | 0 | 0 | View report → |
Water Quality Overview
Rialto, California receives a water quality grade of B with an overall score of 75 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 Rialto. 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 B Means
A grade of B indicates good compliance with EPA drinking water standards. While not perfect, Rialto'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
Lead testing data for Rialto is currently being collected. The EPA requires all community water systems to test for lead under the Lead and Copper Rule.
With 58% of homes built before 1986, Rialto 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
Rialto is in EPA Radon Zone 2 (Moderate risk). Testing is recommended, especially for homes with basements or ground-level living spaces.
Water Systems Serving Rialto
Rialto is served by 2 community water systems regulated under the Safe Drinking Water Act. These systems collectively serve approximately 158,951 people across 2 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 Rialto
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
Rialto vs. Nearby California Cities
How Rialto's water quality compares to similar cities in California:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| Rialto | B | 0 | 2 | 158,951 |
| Sunnyvale | B | 0 | 1 | 157,566 |
| San Dimas | A | 0 | 5 | 156,943 |
| Roseville | B | 3 | 5 | 155,825 |
Common Questions About Rialto Water
These are the most common questions residents search for about water quality in Rialto, California:
Is Rialto water hard or soft? Water hardness varies by source. Rialto's 2 water systems use multiple sources. Check your ZIP code report for specific hardness data.
Can I drink Rialto tap water? Rialto's water receives a grade of B (75/100). No health-based violations have been recorded, but home testing is always recommended.
What is the best water filter for Rialto? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
Rialto vs. California Average
Understanding how Rialto 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 Rialto.
ZIP Codes in Rialto
Rialto spans 2 ZIP codes. 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.