Wahiawa
EPA ID: HI0000333 · 23,348 people served · 42 ZIP codes
Five clean years on EPA record — Wahiawa, 23,348 residents served.
Data: EPA SDWIS Last verified: 2026-04-02
Service Area Map
Coverage area for Wahiawa Source: EPA SDWIS service area boundaries.
Service area boundary
Service Area Demographics
The Wahiawa serves a community with a median household income of $91,697 and an estimated 456,764 residents across its service area. Approximately 73% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
💧 Where Does Your Water Come From?
Wahiawa's water is pumped from underground aquifers. 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.
About 2% of homes in Honolulu County, Hawaii 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. Groundwater sources near contaminated sites may face elevated risk from industrial chemicals.
Infrastructure Risk
PFAS Detected in Service Area
PFAS ("forever chemicals") have been detected in water serving this system's area. 11 detections recorded.
Comparable Water Systems
Similar-sized systems in Hawaii
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
Wahiawa (EPA ID: HI0000333) is a community water system in Hawaii that serves approximately 23,348 people from groundwater sources.
This system provides water to 42 ZIP codes across 2 communities.
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: 1 ZIP code confirmed via EPA Community Water System Service Area Boundaries v3 plus 41 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.
This system serves 42 ZIP codes:
96786 · 96801 · 96802 · 96803 · 96804 96805 · 96806 · 96807 · 96808 · 96809 96810 · 96811 · 96812 · 96813 · 96814 96815 · 96816 · 96817 · 96818 · 96819 96820 · 96821 · 96822 · 96823 · 96824 96825 · 96826 · 96828 · 96830 · 96836 96837 · 96838 · 96839 · 96840 · 96841 96843 · 96844 · 96846 · 96847 · 96848 96849 · 96850
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for Wahiawa (HI0000333) on EPA.gov.
Frequently Asked Questions
Is Wahiawa water safe to drink?
Based on EPA records, Wahiawa has no recorded violations in the past 5 years — a positive indicator of water quality management.
How many people does Wahiawa serve?
Wahiawa serves approximately 23,348 people across 42 ZIP codes in Hawaii.
Where does Wahiawa get its water?
The primary water source is groundwater.
Federal UCMR5 PFAS Monitoring: Tested Clean
This water system was tested under the federal EPA Unregulated Contaminant Monitoring Rule (UCMR5). No PFAS compounds were detected.
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.
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.