Yellowstone County, Montana
26 ZIP codes · Avg score 68/100 · Grade C · Updated 2026-06-03
Although much of Yellowstone County meets baseline standards, some of its 26 ZIP codes show violations that merit closer attention.
How Yellowstone County Compares
How Yellowstone County Compares
Yellowstone County scores 13 points above the Montana state average (55/100) and 0 points above the national average (68/100).
Data: EPA SDWIS Last verified: 2026-06-03
ZIP Code Risk Map
Water Quality Map: Yellowstone County, Montana
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 10%)
Estimated additional annual cost per homeowner: $1,135, driven primarily by flood
Infrastructure: 0.313% avg pipe failure probability, 15% of ZIPs at high risk
50.8% of homes built before 1978 (lead paint era)
Violation History (2021–2025)
↓ Improving trendEPA violation counts by year across Yellowstone County water systems. Health-based shown in red, total in blue.
Peak year: 2022 with 3 violations. Past 5 years: 8 total (8 health-based). Health-based violations are declining versus the prior 2-year window.
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: $1,135
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
73,548 housing units in Yellowstone 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 Yellowstone County
Remediation costs are relatively manageable for most homeowners in Yellowstone 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 Yellowstone 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 Yellowstone County ranked by EPA violation count.
| # | Water System | Population | Violations |
|---|---|---|---|
| 1 | Lockwood Water and Sewer District | 5,900 | 477 |
| 2 | City of Billings | 114,000 | 476 |
| 3 | Company Water District of Billings Heights | 12,000 | 476 |
| 4 | Pioneer Water Service | 900 | 476 |
| 5 | Meadowlark of Billings Llc | 800 | 476 |
18 total water systems serve Yellowstone County.
All ZIP Codes in Yellowstone County
26 ZIP codes tracked in Yellowstone County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 59037 | Huntley | 78 | B | 1 | $326K |
| 2 | 59079 | Shepherd | 77 | B | 9 | $350K |
| 3 | 59104 | Billings | 75 | B | 34 (5 health) | — |
| 4 | 59103 | Billings | 73 | B | 34 (5 health) | — |
| 5 | 59107 | Billings | 73 | B | 34 (5 health) | — |
| 6 | 59108 | Billings | 73 | B | 34 (5 health) | — |
| 7 | 59111 | Billings | 73 | B | 34 (5 health) | — |
| 8 | 59112 | Billings | 73 | B | 34 (5 health) | — |
| 9 | 59114 | Billings | 73 | B | 34 (5 health) | — |
| 10 | 59115 | Billings | 73 | B | 34 (5 health) | — |
| 11 | 59116 | Billings | 73 | B | 34 (5 health) | — |
| 12 | 59117 | Billings | 73 | B | 34 (5 health) | — |
| 13 | 59044 | Laurel | 72 | B | 7 (1 health) | $317K |
| 14 | 59102 | Billings | 70 | B | 34 (5 health) | $307K |
| 15 | 59105 | Billings | 70 | B | 34 (5 health) | $315K |
| 16 | 59106 | Billings | 70 | B | 34 (5 health) | $483K |
| 17 | 59015 | Broadview | 67 | C | 3 | $229K |
| 18 | 59101 | Billings | 65 | C | 34 (5 health) | $243K |
| 19 | 59063 | Park City | 63 | C | 0 | $337K |
| 20 | 59064 | Pompeys Pillar | 63 | C | 0 | $277K |
| 21 | 59075 | Saint Xavier | 63 | C | 0 | $211K |
| 22 | 59088 | Worden | 55 | C | 0 | $226K |
| 23 | 59006 | Ballantine | 53 | D | 0 | $241K |
| 24 | 59057 | Molt | 53 | D | 0 | $423K |
| 25 | 59843 | Helmville | 53 | D | 0 | $298K |
| 26 | 59854 | Ovando | 53 | D | 0 | $475K |
Recommended Buyer Guides for Yellowstone County
Designed to find the guide that fits the county, not the other way around — the system reads EPA detections, FEMA hazard layers, and CDC lead-exposure markers, then outputs the categories that resolve those specific risks for households here, with NSF-certified products surfaced when the matching contaminant appears in the local monitoring data.
- Best Lead Paint Test Kits — 50.8% of homes built before 1978
- Best Under-Sink Reverse Osmosis Systems — Multi-contaminant removal at the kitchen tap
- Best Sump Pumps — Flood is the top compound risk factor
- Best Mold Test Kits — Flood-driven moisture and mold risk
Deep Dive Reports
Detailed analysis for Yellowstone County, Montana
Overview
Yellowstone County in Montana covers 26 ZIP codes with an average Home Safety Score of C (68/100).
18 of 26 ZIP codes have recorded EPA violations. 71 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.