Black Diamond Water Department
EPA ID: WA5307220 · 2,420 people served · 4 ZIP codes
Black Diamond Water Department carries zero EPA violations in five years — a spotless record for a utility serving 2,420 residents.
Data: EPA SDWIS Last verified: 2026-04-02
Service Area Map
Coverage area for Black Diamond Water Department Source: EPA SDWIS service area boundaries.
Service area boundary — Grade A
Service Area Demographics
The Black Diamond Water Department serves a community with a median household income of $130,674 and an estimated 98,284 residents across its service area.
💧 Where Does Your Water Come From?
Black Diamond Water Department'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 King County, Washington 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 70th 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. 21 detections recorded. 4 exceed federal EPA limits (4 ppt for PFOA/PFOS).
Comparable Water Systems
Similar-sized systems in Washington
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
Black Diamond Water Department (EPA ID: WA5307220) is a community water system in Washington that serves approximately 2,420 people from groundwater sources.
This system provides water to 4 ZIP codes across 4 communities.
Average Home Safety Score: A (95/100)
Based on water quality violations, lead levels, and radon risk across all ZIP codes served by this system.
Violation History
Lead & Copper
EPA Lead and Copper Rule sampling data for ZIP codes served by this system:
| ZIP Code | Lead Level | Exceeds Limit | Sample Date |
|---|---|---|---|
| 98010 | 0.002 mg/L | No | N/A |
Radon Risk in Service Area
Dominant radon zone for ZIP codes served by this system: Zone 3 (Low Risk)
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 WA 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 the full compliance record for Black Diamond Water Department (WA5307220) on EPA.gov.
Frequently Asked Questions
Is Black Diamond Water Department water safe to drink?
Based on EPA records, Black Diamond Water Department has no recorded violations in the past 5 years — a positive indicator of water quality management.
How many people does Black Diamond Water Department serve?
Black Diamond Water Department serves approximately 2,420 people across 4 ZIP codes in Washington.
Where does Black Diamond Water Department get its water?
The primary water source is groundwater.
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.