Water Quality in Los Altos, CA: No Violations — Grade A
Grade A · Score 93/100 · 1 water system · Updated 2026-05-03
Los Altos's water meets all EPA standards with no health-based violations.
Data: EPA Safe Drinking Water Information System (SDWIS) Last verified: 2026-05-03
For households in Los Altos, CA, the EPA compliance record offers a straightforward finding: 1 water system are on file, zero violations documented across the entire dataset, and no regulatory actions have been taken against any local utility under the federal Safe Drinking Water Act in any reporting period covered by available SDWIS data.
Water Quality by ZIP Code in Los Altos
Water quality varies across Los Altos's 3 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 94022 | B | 78 | 0 | 0 | View report → |
| 94024 | B | 78 | 0 | 0 | View report → |
| 94023 | B | 83 | 0 | 0 | View report → |
Water Quality Overview
Los Altos, California receives a water quality grade of A with an overall score of 93 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
No EPA violations have been recorded for the 1 water system serving Los Altos. 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 A Means
A grade of A indicates excellent compliance with EPA drinking water standards. Los Altos's water systems have maintained strong performance in both contaminant monitoring and regulatory compliance.
Lead Levels
The average 90th percentile lead level across Los Altos water systems is 0.0023 mg/L — within EPA limits. No ZIP codes exceed the EPA lead action level.
With 75% of homes built before 1986, Los Altos 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.
Water Systems Serving Los Altos
Los Altos is served by 1 community water system regulated under the Safe Drinking Water Act. These systems collectively serve approximately 200 people across 3 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 Los Altos
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
Los Altos vs. Nearby California Cities
How Los Altos's water quality compares to similar cities in California:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| Los Altos | A | 0 | 1 | 200 |
| Sierraville | B | 0 | 1 | 200 |
| Soulsbyville | B | 5 | 1 | 195 |
| Bonita | B | 18 | 1 | 193 |
Water Quality by ZIP Code in Los Altos
Water quality varies across Los Altos's ZIP codes. The table below shows the worst-scoring and best-scoring areas:
Common Questions About Los Altos Water
These are the most common questions residents search for about water quality in Los Altos, California:
Is Los Altos water hard or soft? Water hardness varies by source. Los Altos's 1 water system uses a single source. Check your ZIP code report for specific hardness data.
Can I drink Los Altos tap water? Los Altos's water receives a grade of A (93/100). No health-based violations have been recorded, but home testing is always recommended.
What is the best water filter for Los Altos? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
Los Altos vs. California Average
Understanding how Los Altos 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 Los Altos.
ZIP Codes in Los Altos
Los Altos spans 3 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 A 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.