Walla Walla Water Division
EPA ID: WA5392500 · 42,959 people served · 1 ZIP code
Compliance tracking for Walla Walla Water Division shows 3 pending violations logged in the EPA system — the supplier delivers water to approximately 42,959 residents while those findings remain open.
Data: EPA SDWIS Last verified: 2026-04-02
Service Area Map
Coverage area for Walla Walla Water Division Source: EPA SDWIS service area boundaries.
Service area boundary — Grade C
Service Area Demographics
The Walla Walla Water Division serves a community with a median household income of $70,660 and an estimated 42,794 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?
Walla Walla Water Division'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 2% of homes in Walla Walla County, Washington rely on private wells rather than public water systems. Private well owners are responsible for their own water testing and treatment.
Infrastructure Risk
Detected Contaminants
How Walla Walla Water Division compares to EPA limits
What This Means For You
Total Trihalomethanes (TTHM) at 2 mg/L exceeds the EPA maximum of 0.08 mg/L. Bladder & rectal cancer risk; reproductive concerns. Consider granular activated carbon (GAC) filtration.
Haloacetic Acids (HAA5) at 1 mg/L exceeds the EPA maximum of 0.06 mg/L. Cancer risk; reproductive & developmental effects. Consider granular activated carbon (GAC) filtration.
Contaminant 2440 at 5 mg/L exceeds the EPA maximum of mg/L.
Contaminant 2959 at 1 mg/L exceeds the EPA maximum of mg/L.
Surface Water Treatment Rule at 1 mg/L exceeds the EPA maximum of mg/L.
Total Trihalomethanes (TTHM) was detected in this water system. granular activated carbon (GAC) filtration can reduce exposure.
Find a certified water filter →Comparable Water Systems
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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
Walla Walla Water Division (EPA ID: WA5392500) is a community water system in Washington that serves approximately 42,959 people from surface water sources.
This system serves ZIP code 99362 in Walla Walla.
Average Home Safety Score: C (69/100)
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, 2025 | Surface Water Treatment Rule | Monitoring | Resolved |
| January 1, 2024 | Total Trihalomethanes (TTHM) | Monitoring | Unresolved |
| October 1, 2023 | Contaminant 2440 | Monitoring | Resolved |
| July 1, 2023 | Contaminant 2959 | Monitoring | Unresolved |
| January 1, 2023 | Contaminant 2440 | Monitoring | Unresolved |
Contaminants Detected
The following contaminants have been flagged in EPA records for this water system:
| Contaminant | Category | Violations | Health-Based |
|---|---|---|---|
| Contaminant 2440 | Other Violation | 5 | No |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 2 | No |
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 1 | No |
| Contaminant 2959 | Other Violation | 1 | No |
| Surface Water Treatment Rule | Treatment Failure | 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 |
|---|---|---|---|
| 99362 | 0.0025 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: 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.
- 99362 — Walla Walla
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for Walla Walla Water Division (WA5392500) on EPA.gov.
Frequently Asked Questions
Is Walla Walla Water Division water safe to drink?
Walla Walla Water Division has only monitoring/reporting violations, which are procedural in nature. The system meets federal health-based standards.
How many people does Walla Walla Water Division serve?
Walla Walla Water Division serves approximately 42,959 people across 1 ZIP code in Washington.
Where does Walla Walla Water Division get its water?
The primary water source is surface water.
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.
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
Walla Walla Water Division (EPA ID: WA5392500) — request the latest Consumer Confidence Report or ask about specific contaminants.