Guadalupe Valley Mid
EPA ID: CA4110005 · 1,472 people served · 1 ZIP code
EPA monitoring data for Guadalupe Valley Mid shows an unblemished five-year compliance history — no violations of any kind have been recorded for this utility, which supplies water to approximately 1,472 people, covering every reporting cycle without a single MCL exceedance or monitoring lapse.
Data: EPA SDWIS Last verified: 2026-04-02
Service Area Map
Coverage area for Guadalupe Valley Mid Source: EPA SDWIS service area boundaries.
Service area boundary
Service Area Demographics
The Guadalupe Valley Mid serves a community with a median household income of $151,593 and an estimated 4,718 residents across its service area. Approximately 68% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
🌊 Where Does Your Water Come From?
Guadalupe Valley Mid's water is drawn from rivers, lakes, or reservoirs. Surface water sources are more exposed to agricultural runoff, stormwater, and upstream discharges, but they typically receive more intensive treatment before reaching your tap.
About 1% of homes in San Mateo County, California rely on private wells rather than public water systems. Private well owners are responsible for their own water testing and treatment.
Superfund Proximity Note: This service area ranks in the 60th percentile nationally for proximity to Superfund (NPL) sites.
Infrastructure Risk
PFAS Detected in Service Area
PFAS ("forever chemicals") have been detected in water serving this system's area. 6 detections recorded. 2 exceed federal EPA limits (4 ppt for PFOA/PFOS). 2 exceed state limits.
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
Guadalupe Valley Mid (EPA ID: CA4110005) is a community water system in California that serves approximately 1,472 people from surface water sources.
This system serves ZIP code 94005 in Brisbane.
Violation History
Lead & Copper
No Lead and Copper Rule sampling data available for this water system.
Need help with your water quality?
Typical cost: Water test: typically $20–$50 (DIY kit) · Professional inspection: $150–$400
Find the Right Water FilterFree tip: Let cold water run for 2 minutes before drinking — this helps flush lead from your pipes.
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.
- 94005 — Brisbane
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for Guadalupe Valley Mid (CA4110005) on EPA.gov.
Frequently Asked Questions
Is Guadalupe Valley Mid water safe to drink?
Based on EPA records, Guadalupe Valley Mid has no recorded violations in the past 5 years — a positive indicator of water quality management.
How many people does Guadalupe Valley Mid serve?
Guadalupe Valley Mid serves approximately 1,472 people across 1 ZIP code in California.
Where does Guadalupe Valley Mid get its water?
The primary water source is surface water.
Federal UCMR5 PFAS Monitoring: Detected
This water system was tested under the federal EPA Unregulated Contaminant Monitoring Rule (UCMR5). PFAS compounds were detected below the current state-enforceable MCL.
Current MCL reflects the lowest state-enforceable limit (NYS 10 ppt for PFOA/PFOS, effective August 2020). The federal final MCL of 4 ppt for PFOA/PFOS (EPA April 2024 rule) is not enforceable until April 2029. Detections above 4 ppt but below 10 ppt are below current MCL but above the future federal limit.
Source: U.S. EPA UCMR5 (Unregulated Contaminant Monitoring Rule, 5th cycle) — per-system federal sampling, 2023–2025. EPA UCMR5 monitoring program →
Lead Service Line Inventory
Service line breakdown reported under the federal Lead and Copper Rule Improvements (LCRI) inventory requirement:
This system reports zero confirmed lead service lines in its inventory. Unknown-material counts may still warrant verification.
Federal LCRI rule (effective October 2024) requires every public water system to inventory its service lines and complete lead-line replacement within 10 years.
Source: EPA SDWIS Federal Service Line Inventory (Phase 2) · Submitted 2026
ZipCheckup is not affiliated with the utility or state agency. Inventory figures render verbatim from the public LCRI submission cited above; ZipCheckup does not perform inspections or replacements.