Treasure Island
EPA ID: CA3810702 · 3,864 people served · 4 ZIP codes
Looking at the EPA enforcement file for Treasure Island, 7 violations are listed as unresolved — those findings cover the utility's service area of approximately 3,864 people and remain open in the federal compliance system, awaiting formal corrective action documentation.
Data: EPA SDWIS Last verified: 2026-04-02
Compliance Trajectory
Stable · Risk tier: High · 85% chance of violation in next 12 months
Violations went from 1 (2021) to 2 (2024). Violation counts have remained relatively steady.
Service Area Map
Coverage area for Treasure Island Source: EPA SDWIS service area boundaries.
Service area boundary — Grade D
Service Area Demographics
The Treasure Island serves a community with a median household income of $119,500 and an estimated 109,140 residents across its service area. Approximately 89% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
🌊 Where Does Your Water Come From?
Treasure Island'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 63th percentile nationally for proximity to Superfund (NPL) sites.
Infrastructure Risk
Detected Contaminants
How Treasure Island compares to EPA limits
What This Means For You
Lead at 1 mg/L (action level) exceeds the EPA maximum of 0.015 mg/L (action level). Brain damage in children, kidney & blood pressure in adults. Consider reverse osmosis filtration.
Contaminant 0700 at 6 mg/L exceeds the EPA maximum of mg/L.
PFAS Detected in Service Area
PFAS ("forever chemicals") have been detected in water serving this system's area. 1 detection recorded.
Lead was detected in this water system. reverse osmosis filtration can reduce exposure.
Find a certified water filter →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
Treasure Island (EPA ID: CA3810702) is a community water system in California that serves approximately 3,864 people from surface water sources.
This system provides water to 4 ZIP codes across 3 communities.
Average Home Safety Score: D (53/100)
Based on water quality violations, lead levels, and radon risk across all ZIP codes served by this system.
Violation History
Recent Violations
| Date | Contaminant | Type | Status |
|---|---|---|---|
| July 1, 2024 | Contaminant 0700 | Health-based | Unresolved |
| June 1, 2024 | Contaminant 0700 | Health-based | Unresolved |
Contaminants Detected
The following contaminants have been flagged in EPA records for this water system:
| Contaminant | Category | Violations | Health-Based |
|---|---|---|---|
| Contaminant 0700 | Other Violation | 6 | Yes |
| Lead | Inorganic | 1 | No |
Lead & Copper
EPA Lead and Copper Rule sampling data for ZIP codes served by this system:
| ZIP Code | Lead Level | Exceeds Limit | Sample Date |
|---|---|---|---|
| 94130 | 0.00305 mg/L | No | N/A |
Radon Risk in Service Area
Dominant radon zone for ZIP codes served by this system: Zone 2 (Moderate Risk)
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
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: 2 ZIP codes confirmed via EPA Community Water System Service Area Boundaries v3 plus 2 additional ZIPs inferred from SDWIS registry data. The EPA-confirmed set is the most reliable; SDWIS-inferred entries may be narrower than the real deployment area.
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for Treasure Island (CA3810702) on EPA.gov.
Frequently Asked Questions
Is Treasure Island water safe to drink?
Treasure Island has recorded 6 health-based violations in the past 5 years. While the system is required to treat water to meet federal standards, you may want to consider additional precautions such as a certified water filter.
How many people does Treasure Island serve?
Treasure Island serves approximately 3,864 people across 4 ZIP codes in California.
Where does Treasure Island get its water?
The primary water source is surface water.
Contact Your Water Utility
Public-record contact information for the water utility serving this system. Use these channels to request water quality reports, ask about service, or report issues directly.
Contact information from Treasure Island Consumer Confidence Report.
ZipCheckup is not affiliated with this water utility, does not act as its agent, and does not provide customer support for it. Contact details shown are public-record information from CCR filings. For service issues, contact the utility directly using the information above.
Water Source & Treatment
Where this water originates and how it's treated before reaching your tap.
Source: Treasure Island Consumer Confidence Report.
ZipCheckup is not affiliated with this water utility. Treatment and source data are sourced from the utility's published CCR filings.
The Hetch Hetchy water source was granted a filtration exemption due to its pristine and protected watershed status. Annual watershed surveys evaluate sanitary conditions, potential contamination sources (wildlife, stock, human activities), and management activities in partnership with agencies like the National Park Service and US Forest Service.
Treatment regime
How this utility classifies its treatment process and what each reported treatment chemical does.
Treatment chemicals and what each one does
Chemical names are reported verbatim by the utility. Purpose categories are ZipCheckup annotations based on standard drinking-water treatment practice.
Watershed exposure sources reported
Land-use and natural conditions identified in the utility's source-water assessment as potential contamination sources upstream of treatment.
Treatment classification and chemical list sourced from Treasure Island Consumer Confidence Report.
Treatment intensity is a ZipCheckup-derived classification based on the chemicals and processes the utility reports. Chemicals and contamination sources are taken verbatim from the utility's CCR filing. Routine federal monitoring and contaminant testing shown elsewhere on this page determine whether the water meets safety standards, not the treatment classification.
Lead Service Line Replacement Tracker
This water utility's lead service line (LSL) replacement program is tracked from public Consumer Confidence Report filings. Email signup notifies subscribers when the utility files an updated replacement plan or progress milestone.
Treasure Island
ZipCheckup is not affiliated with this water utility. LSL replacement-program data is sourced from public CCR filings published by the utility. Subscription notifications are based on automated parsing of subsequent CCR releases.
Learn more about Lead and Copper Rule replacement requirements →
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.
Aesthetic water quality
These measurements describe the look, taste, and feel of the water this utility delivers. They are not contaminant violations — they sit alongside federal Secondary Maximum Contaminant Levels (SMCLs) which the EPA publishes as non-enforceable guidance.
Aesthetic measurements from Treasure Island Consumer Confidence Report.
Aesthetic measurements are reported by the utility from its annual sampling. EPA Secondary MCLs are advisory thresholds — values outside them indicate aesthetic concerns such as taste or appearance, not health violations. Federal contaminant testing is shown in the sections above.
Notable events and violations
This section summarizes events the utility chose to disclose in its most recent Consumer Confidence Report, plus any federal compliance violations the utility recorded against itself. Both lists are utility-authored — ZipCheckup does not audit, judge, or reorder them.
Federal compliance violations on record
These entries are taken verbatim from the utility's CCR violations section. EPA defines four broad violation categories: Maximum Contaminant Level (MCL), Treatment Technique (TT), Monitoring & Reporting (M&R), and Public Notification (PN).
-
MCL · LeadDate not published
2 out of 19 water samples collected at consumer taps had lead concentration above the Action Level (15 ppb).
Violations record from Treasure Island Consumer Confidence Report.
Notable events from the utility's CCR
These bullet entries are the utility's own narration of operational, regulatory, or infrastructure events during the reporting period.
- In 2011, the Testa Ultraviolet Treatment Facility (UV disinfection plant) was brought online to provide advanced disinfection targeting biological pathogens.
ZipCheckup note: items above reflect what the utility published in its most recent CCR. Federal violation records are also tracked separately by the EPA Safe Drinking Water Information System (SDWIS) — the SDWIS record is the authoritative federal source for any specific regulatory action.
Frequently Asked Questions
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
Treasure Island (EPA ID: CA3810702) — request the latest Consumer Confidence Report or ask about specific contaminants.