Grant County, Washington
16 ZIP codes · Avg score 74/100 · Grade B · Updated 2026-06-03
Although county size varies, Grant County's 16 ZIP codes share reliably safe tap water records and above-average compliance scores.
How Grant County Compares
How Grant County Compares
Grant County scores 4 points below the Washington state average (78/100) and 6 points above the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: Grant County, Washington
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 12.6 (asthma 10.8%, diabetes 11.5%)
Estimated additional annual cost per homeowner: $915, driven primarily by energy_code_gap
Infrastructure: 0.354% avg pipe failure probability, 19% of ZIPs at high risk
60.1% of homes built before 1978 (lead paint era)
Violation History (2023–2025)
→ Stable trendEPA violation counts by year across Grant County water systems. Health-based shown in red, total in blue.
Peak year: 2023 with 1 violation. Past 5 years: 3 total (3 health-based).
Source: EPA SDWIS historical violations. Data may lag 6–12 months for the most recent year.
County Health Indicators vs National Average
Black markers indicate national averages. Source: CDC PLACES, Census ACS.
Infrastructure Overview
Sources: Census ACS (housing age), EPA SDWIS (infrastructure risk model), state bridge inspection data.
Compound Risk Breakdown
Estimated additional annual cost per homeowner: $915
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
38,490 housing units in Grant County
Source: U.S. Census Bureau ACS B25034 (Year Structure Built).
Water Safety Affordability
How much it costs to fix water issues relative to home values in Grant County
Remediation costs are relatively manageable for most homeowners in Grant County, representing a small fraction of property value.
Remediation includes water filtration, lead abatement, radon mitigation, and flood protection where applicable. Source: Census ACS, EPA SDWIS.
Health Outcomes vs National Average
CDC PLACES data for Grant County residents
Black markers = national averages. Red = above national avg. Green = below. Source: CDC PLACES, Census ACS.
Water Systems with Most Violations
Top 5 systems in Grant County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | City of Moses Lake | 32,428 | 40 |
| 2 | Soap Lake Water Department | 2,399 | 25 |
| 3 | Cascade Valley Water District | 379 | 16 |
| 4 | Stratford Road Estates | 312 | 16 |
| 5 | Hillcrest Water Users Assn | 300 | 16 |
34 total water systems serve Grant County.
All ZIP Codes in Grant County
16 ZIP codes tracked in Grant County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 98851 | Soap Lake | 83 | B | 1 | $241K |
| 2 | 99123 | Electric City | 83 | B | 1 | $248K |
| 3 | 99133 | Grand Coulee | 83 | B | 0 | $221K |
| 4 | 99321 | Beverly | 83 | B | 0 | — |
| 5 | 99357 | Royal City | 83 | B | 1 | $307K |
| 6 | 99349 | Mattawa | 82 | B | 12 (1 health) | $409K |
| 7 | 98824 | George | 81 | B | 4 | $180K |
| 8 | 99115 | Coulee City | 79 | B | 5 | $208K |
| 9 | 98832 | Marlin | 78 | B | 5 (1 health) | $259K |
| 10 | 98857 | Warden | 78 | B | 4 | $194K |
| 11 | 98848 | Quincy | 75 | B | 11 | $309K |
| 12 | 98837 | Moses Lake | 72 | B | 16 | $290K |
| 13 | 98823 | Ephrata | 70 | B | 13 | $256K |
| 14 | 98853 | Stratford | 53 | D | 0 | — |
| 15 | 98860 | Wilson Creek | 53 | D | 0 | $184K |
| 16 | 99135 | Hartline | 53 | D | 0 | $198K |
Recommended Buyer Guides for Grant County
If FEMA records flag flood-top-risk status or EPA samples show PFAS exceedances, the matching logic lifts emergency-water and PFAS-rated filtration into the recommendations — federal data drives the order, not retailer arrangements.
- Best Lead Paint Test Kits — 60.1% of homes built before 1978
Deep Dive Reports
Detailed analysis for Grant County, Washington
Overview
Grant County in Washington covers 16 ZIP codes with an average Home Safety Score of B (74/100).
11 of 16 ZIP codes have recorded EPA violations. 2 health-based violations have been documented.
← Back to Washington water quality report
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Home values: U.S. Census Bureau ACS (median estimates by ZCTA)
Updated daily.