Fergus County, Montana
11 ZIP codes · Avg score 49/100 · Grade D · Updated 2026-06-03
Covering 11 ZIP codes, Fergus County falls in the bottom tier for tap water safety — health-based violations are a recurring pattern, and the county's grade signals that residents should check system-level detail for their specific address.
How Fergus County Compares
How Fergus County Compares
Fergus County scores 6 points below the Montana state average (55/100) and 19 points below the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: Fergus County, Montana
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Health risk index: 13.9 (asthma 11.2%, diabetes 11.8%)
Estimated additional annual cost per homeowner: $881, driven primarily by wildfire
Infrastructure: 0.421% avg pipe failure probability, 50% of ZIPs at high risk
62.9% of homes built before 1978 (lead paint era)
Violation History (2021–2026)
↑ Worsening trendEPA violation counts by year across Fergus County water systems. Health-based shown in red, total in blue.
Peak year: 2025 with 28 violations. Past 5 years: 45 total (45 health-based). Health-based violations are rising versus the prior 2-year window — worth closer monitoring.
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: $881
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
6,054 housing units in Fergus 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 Fergus County
Remediation costs are relatively manageable for most homeowners in Fergus 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 Fergus 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 Fergus County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | DENTON TOWN OF | 255 | 61 |
| 2 | LEWISTOWN CITY OF | 5,923 | 27 |
| 3 | Mountain Acres Mb Hm Pk | 320 | 27 |
| 4 | King Ranch Colony | 56 | 27 |
| 5 | Deerfield Hutterite Colony | 51 | 27 |
11 total water systems serve Fergus County.
All ZIP Codes in Fergus County
11 ZIP codes tracked in Fergus County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 59032 | Grass Range | 67 | C | 4 | $123K |
| 2 | 59489 | Winifred | 65 | C | 4 (1 health) | — |
| 3 | 59464 | Moore | 63 | C | 2 | $242K |
| 4 | 59471 | Roy | 63 | C | 3 | $150K |
| 5 | 59430 | Denton | 45 | D | 61 (58 health) | $211K |
| 6 | 59084 | Teigen | 40 | D | 0 | — |
| 7 | 59424 | Coffee Creek | 40 | D | 0 | $265K |
| 8 | 59441 | Forest Grove | 40 | D | 0 | $229K |
| 9 | 59451 | Hilger | 40 | D | 0 | $120K |
| 10 | 59457 | Lewistown | 40 | D | 27 (19 health) | $206K |
| 11 | 59535 | Lloyd | 40 | D | 0 | — |
Recommended Buyer Guides for Fergus County
Where county records show a lead exceedance or pre-1978 housing concentration, lead-specific filters and test kits move toward the top of the list.
- Best Lead Paint Test Kits — 62.9% of homes built before 1978
- Best Under-Sink Reverse Osmosis Systems — Multi-contaminant removal at the kitchen tap
- Best Radon Test Kits — EPA Radon Zone 1 (highest risk) dominant in county
- Best HEPA Air Purifiers for Wildfire Smoke — Wildfire is the top compound risk factor
Deep Dive Reports
Detailed analysis for Fergus County, Montana
Overview
Fergus County in Montana covers 11 ZIP codes with an average Home Safety Score of D (49/100).
6 of 11 ZIP codes have recorded EPA violations. 78 health-based violations have been documented.
← Back to Montana 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.
What You Can Do
Fergus County has a grade of D. Here are steps to protect your household.
Test your tap water
Order a certified lab test kit ($20-$50) to check for lead, bacteria, and other contaminants specific to your ZIP code.
Consider a certified water filter
NSF-certified filters can remove most common contaminants. Match the filter to your test results for best protection. Try our filter matcher
Contact your water utility
Request the latest Consumer Confidence Report (CCR) from your water provider. It details exactly what was found in your water supply.
Check for lead in your home
62.9% of homes in this county were built before 1978. Older plumbing and solder can leach lead into drinking water, especially in the morning.