City of Gilroy
EPA ID: CA4310004 · 59,203 people served · 2 ZIP codes
ZipCheckup's reading of EPA records for City of Gilroy (CA4310004): 1 health-based violation recorded since 2021. Past violations at City of Gilroy total 1, all marked resolved; it supplies 59,203 residents.
Data: EPA SDWIS
Service Area Map
Coverage area for City of Gilroy Source: EPA SDWIS service area boundaries.
Service area boundary
Demographics of ZIP Codes Served
The ZIP codes associated with City of Gilroy have a median household income of $146,249 and about 119,462 residents live in those ZIP codes (Census; not the number of people this system supplies). Approximately 49% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
💧 Where Does Your Water Come From?
City of Gilroy's water is classified in EPA records as a groundwater source. Groundwater is naturally filtered through rock and soil, but it can be vulnerable to PFAS contamination, nitrates from agriculture, and industrial chemicals that seep into the water table.
Superfund Proximity Note: This service area ranks in the 80th percentile nationally for proximity to Superfund (NPL) sites. Groundwater sources near contaminated sites may face elevated risk from industrial chemicals.
Infrastructure Risk
PFAS in ZIP Codes This System Serves
PFAS ("forever chemicals") have been reported in samples from water systems associated with the ZIP codes in this system's area. These results can come from other water systems serving the same ZIP codes; check the UCMR5 section for any results reported for this system. 11 detections recorded. 3 detections are above the level of a federal PFAS MCL (4 ppt for PFOA and PFOS), with compliance required from 2029.
Comparable Water Systems
Similar-sized systems in California
Estimated Remediation Costs
Average estimated costs across ZIP codes served by this system
Based on national averages for common remediation projects. Actual costs vary by property. Only issues flagged by EPA, FEMA, or state data for each ZIP code are included.
System Overview
City of Gilroy (EPA ID: CA4310004) is a community water system in California that serves approximately 59,203 people from groundwater sources.
This system provides water to 2 ZIP codes across 2 communities.
Violation History
Status breakdown for accepted records with record years 2021-2026: 1 resolved, 0 archived, 0 addressed, and 0 unaddressed. Under this source contract, current noncompliance is the sum of addressed and unaddressed records. Archived and resolved records are excluded from current noncompliance.
Recent Violations
| Date | Contaminant | Type | Status |
|---|---|---|---|
| June 1, 2022 | Nitrate | Health-based | Resolved |
Contaminants Detected
The following contaminants have been flagged in EPA records for this water system:
| Contaminant | Category | Violations | Health-Based |
|---|---|---|---|
| Nitrate | MCL Violation | 1 | Yes |
Health Risk Details
Lead (EPA level: 0.015 mg/L (EPA action level for the 90th percentile of a system's tap samples; not a safe level))
Brain damage in children, kidney & blood pressure in adults At-risk groups: infants, children under 6, pregnant women.
Treatment options (verify a product is certified to reduce this contaminant): reverse osmosis, distillation, carbon block filter certified for lead reduction (NSF/ANSI 53). Find the right filter →
Lead & Copper
EPA Lead and Copper Rule evidence attributed directly to this water system:
| Lead Level | Exceeds Action Level | Sample Date |
|---|---|---|
| 0.002 mg/L | No | 2024-12-31 |
No copper action-level exceedance record appears for this PWSID in the accepted LCR snapshot. This does not establish a clean copper measurement.
Radon Risk in Service Area
2 of 2 ZIP records with known zones are in EPA Radon Zone 2.
The EPA recommends testing all homes regardless of radon zone. County radon zones cannot replace an in-home radon test.
ZIP Codes Served
Coverage: Service area ZIP codes sourced from EPA Community Water System Service Area Boundaries v3 (March 2026 release). These ZIPs reflect the actual deployment footprint recorded by CA or modeled from parcel and building-footprint data.
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View available EPA compliance records for City of Gilroy (CA4310004) on EPA.gov.
Frequently Asked Questions
Is City of Gilroy water safe to drink?
The accepted 2026Q2 ECHO snapshot shows no current noncompliance for City of Gilroy; its 1 accepted 2021-2026 record are resolved or archived. Historical compliance status does not establish conditions at a specific tap.
How many people does City of Gilroy serve?
City of Gilroy serves approximately 59,203 people across 2 ZIP codes in California.
Where does City of Gilroy get its water?
The primary water source is groundwater.
Federal UCMR5 PFAS Monitoring: Sample Above an EPA MCL Value or State Standard
This water system was tested under the federal EPA Unregulated Contaminant Monitoring Rule (UCMR5). One or more PFAS measurements were above the level of the EPA MCL for that compound (April 2024 rule, which takes effect in 2029) or above an applicable state drinking-water standard; a monitoring result above that level is not by itself a violation.
EPA's April 2024 PFAS rule sets MCLs of 4 ppt for PFOA and PFOS and 10 ppt for PFHxS, PFNA and HFPO-DA (GenX); water systems must comply from 2029. Other PFAS compounds have no individual federal MCL. A state standard is shown only where this system's state has its own enforceable PFAS limit. Detection results are EPA UCMR5 samples, not a measurement at your tap.
Source: U.S. EPA UCMR5 (Unregulated Contaminant Monitoring Rule, 5th cycle) — per-system federal sampling, 2023–2025. EPA UCMR5 monitoring program →
How Water Systems Appear in Rankings
Water systems are evaluated by violation history, contaminant detections, and service population. Larger systems with more service connections appear in more rankings.
- #25 / 50 Highest Exposure Burden (California)
Frequently Asked Questions
How to cite this page
ZipCheckup. (n.d.). City of Gilroy (CA): 1 Health Violation. https://zipcheckup.com/water-system/ca4310004/
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title = {{City of Gilroy (CA): 1 Health Violation}},
year = {n.d.},
url = {https://zipcheckup.com/water-system/ca4310004/}
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What You Can Do
Test your water
Home test kits can detect lead, bacteria, and other contaminants at your tap. Find the right filter →
Check your specific ZIP code
Water quality can vary within a system. View nearest ZIP report →
Contact your utility
City of Gilroy (EPA ID: CA4310004) - request the latest Consumer Confidence Report or ask about specific contaminants.