CITY REPORT WY

Yellowstone National Park, WY: 1 Violation — 66/100 (2026)

1 ZIP code · 1 water system · Updated 2026-06-04

Although much of Yellowstone National Park meets baseline drinking water standards, some WY-tracked service areas show violations that merit a closer look — particularly for older housing stock.

How Yellowstone National Park Compares

Yellowstone National Park66/100
Wyoming avg55/100
National avg67/100

Data: EPA SDWIS Last verified: 2026-06-04

1
ZIP Codes
1
Water Systems
1
ZIPs with Violations
C · 66
Avg Safety Score
Zone 1
Radon Risk (High)
$1,200
Est. Remediation

What You Should Know About Yellowstone National Park Water

  • Your city's water systems recorded 1 violation in the past 5 years.
  • Average lead level: 0.004 mg/L.
  • Homes built before 1986: 56% — older plumbing may contain lead solder.
  • Estimated remediation: $1,200 per household.
  • CDC health risk index: 12.77 — above typical levels.

Who Supplies Your Water in Yellowstone National Park

The structure of water supply in Yellowstone National Park, WY is straightforward: one utility provides the bulk of residential service among 1 tracked system, concentrating rate-setting and infrastructure decisions under a single organization.

Ynp-mammoth Hot Springs
Serves ~2,600 people · 1 violation
66
/100

Overview

We track water quality and home safety data for 1 ZIP code in Yellowstone National Park, Wyoming (population ~739), covering 1 community water system serving approximately 2,600 people region-wide.

1 of 1 ZIP code (100%) have recorded EPA violations. All violations are monitoring/reporting type.

Home Safety Score

Average Home Safety Score for Yellowstone National Park: C (66/100)

The score combines three factors:

Factor What It Measures
Water Quality EPA violations and compliance history
Lead Levels 90th percentile lead concentration vs EPA action level
Radon Risk EPA radon zone classification

Water Sources

Yellowstone National Park water systems draw from: Surface water.

Lead & Copper

  • Average lead level (90th percentile): 0.0040 mg/L (EPA action level: 0.015 mg/L)
  • 0 ZIP codes exceed the EPA lead action level

Radon Risk

Dominant radon zone: Zone 1 (High Risk)

The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.

Top Contaminants

Contaminant Category Violations ZIPs Affected
E. coli Microbiological 2 1

Areas with Most Violations

ZIP Code Safety Score Violations Health-Based System
82190 C 1 0 Ynp-mammoth Hot Springs

All ZIP Codes in Yellowstone National Park

  • 82190 [C] — 1 violation

Data Sources

Updated daily.

Health Outcomes in Yellowstone National Park

9.8%
Asthma (US: 9.8%)
11.7%
Diabetes (US: 10.4%)
14.2%
Poor Mental Health (US: 14.8%)

Source: CDC PLACES (County-level estimates). Water contamination can correlate with respiratory and chronic health conditions.

Compared to National Average

Asthma 9.8% ↓
Diabetes 11.7% ↑
Mental Health 14.2% ↓

Vertical line = national average. Above national · Below national

Top Contaminants in Yellowstone National Park Water

E. coli 2 violations
Microbiological
Gastrointestinal illness, potentially fatal

Based on EPA violation records. Check your ZIP code report for system-specific contaminant data.

Housing & Infrastructure in Yellowstone National Park

1987
Median Build Year
56%
Built Before 1986
22%
Built Before 1970
Copper
Likely Pipe Material

With 56% of homes built before 1986, lead solder in plumbing is a potential concern. The EPA banned lead solder in 1986, but many older homes retain original plumbing.

Source: U.S. Census Bureau American Community Survey (ACS).

Housing Age Profile

Lead solder was standard in copper plumbing until federally banned in 1986; lead pipes were common in service lines pre-1970. Yellowstone National Park's median build year of 1987 reflects a housing stock where these older materials are a pervasive feature — not a rare legacy — of the residential plumbing landscape.

1987
Median Year Built
56%
Pre-1986 (Lead Paint Risk)
22%
Pre-1970 (Lead Pipes Risk)
Pre-1970 (22%) 1970–1986 (34%) Post-1986 (44%)

Over half of homes in Yellowstone National Park were built before 1986, when lead solder was banned. Older plumbing may leach lead into drinking water, especially with corrosive water chemistry.

Source: U.S. Census Bureau ACS B25034.

Lead Exposure Risk for Children in Yellowstone National Park

56%
Homes Built Before 1986
0.004
mg/L Avg Lead (Limit: 0.015)

Why children are most at risk: The CDC states there is no safe level of lead exposure for children. Children under 6 absorb lead more readily than adults, and even low levels can cause developmental delays, learning difficulties, and behavioral problems.

When older housing represents 56% of the local inventory or aggregate readings approach the federal action level, an in-home check becomes the standard way to translate citywide averages into the specific reality of an individual Yellowstone National Park address.

Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.

What You Can Do in Yellowstone National Park

  1. Test your water at home. City-level data shows averages — your tap may differ. NSF-certified test kits cost $20-40 and give results in days.
  2. Install a certified water filter. Filters rated for E. coli can reduce the most common contaminant found in Yellowstone National Park's water.
  3. Check your home's plumbing. With 56% of homes built before 1986, lead solder is a real possibility.

Frequently Asked Questions

Is the water safe to drink in Yellowstone National Park, WY?
Yellowstone National Park has an average water safety score of 66/100 (Grade C). 1 EPA violation has been recorded. Check individual ZIP code reports for details specific to your neighborhood.
How many water violations does Yellowstone National Park have?
Yellowstone National Park water systems have a total of 1 EPA violation. Violations are tracked across 1 ZIP code.
Does Yellowstone National Park water have lead?
The average 90th-percentile lead level in Yellowstone National Park is 0.004 mg/L. This is below the EPA action level of 0.015 mg/L. Lead levels can vary by home — testing is recommended especially in older properties.
How does Yellowstone National Park compare to Wyoming average?
Yellowstone National Park has an average water safety score of 66/100, which is above the Wyoming state average of 55/100.
How many water systems serve Yellowstone National Park?
Yellowstone National Park is served by 1 public water system across 1 ZIP code, serving approximately 739 people.
How much does it cost to fix water issues in Yellowstone National Park?
Estimated remediation costs in Yellowstone National Park average $1,200 per household, ranging from $800 to $1,500. Costs include filtration, pipe replacement, radon mitigation, and flood protection.
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