CITY REPORT ID

May, ID: High Radon Risk — 53/100 (2026)

1 ZIP code · 1 water system · Updated 2026-06-03

May, ID water systems: poor compliance record, lower-tier safety grade.

How May Compares

May53/100
Idaho avg66/100
National avg67/100

Data: EPA SDWIS Last verified: 2026-06-03

1
ZIP Codes
1
Water Systems
0
ZIPs with Violations
D · 53
Avg Safety Score
Zone 1
Radon Risk (High)
$3,000
Est. Remediation

What You Should Know About May Water

  • Homes built before 1986: 63% — older plumbing may contain lead solder.
  • Estimated remediation: $3,000 per household.
  • CDC health risk index: 14.15 — above typical levels.

Who Supplies Your Water in May

Across most of May, ID, residential water comes from a single utility. That provider sets rates, manages infrastructure maintenance, and files compliance reports with the EPA on behalf of the households it serves. Federal tracking data shows 1 system on record, but one carries the bulk of the service load.

CHALLIS CITY OF
Serves ~900 people
53
/100

Overview

We track water quality and home safety data for 1 ZIP code in May, Idaho (population ~98), covering 1 community water system serving approximately 900 people region-wide.

No EPA violations recorded across any ZIP codes in May — an excellent indicator of water quality.

Home Safety Score

Average Home Safety Score for May: D (53/100)

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

May water systems draw from: Surface water.

Lead & Copper

  • Lead data: not yet available for May
  • 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.

Areas with No Violations

ZIP Code Safety Score System Population
83253 D CHALLIS CITY OF 900

All ZIP Codes in May

Data Sources

Updated daily.

Health Outcomes in May

10.8%
Asthma (US: 9.8%)
12.7%
Diabetes (US: 10.4%)
14.8%
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 10.8% ↑
Diabetes 12.7% ↑
Mental Health 14.8% ↓

Vertical line = national average. Above national · Below national

Housing & Infrastructure in May

1972
Median Build Year
63%
Built Before 1986
8%
Built Before 1970
Copper
Likely Pipe Material

With 63% 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

What does a median build year of 1972 mean for water safety in May? It means the majority of the city's residential plumbing was installed before 1986, when lead solder was federally banned, and a large share may predate 1970, when lead pipes were commonly used — making plumbing age a central variable in household-level lead risk across much of the city.

1972
Median Year Built
63%
Pre-1986 (Lead Paint Risk)
8%
Pre-1970 (Lead Pipes Risk)
Pre-1970 (8%) 1970–1986 (55%) Post-1986 (37%)

Over half of homes in May 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 May

63%
Homes Built Before 1986

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.

If 63% of the May inventory comes from before the federal ban on lead-bearing solder — and if utility samples sit at or near 0.015 mg/L — the gap between citywide averages and one specific faucet becomes a practical concern rather than a theoretical one. That is why one-home reads exist as a separate measurement. A certified filter through retailer networks addresses confirmed exposure where it appears in a household.

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

Flood & Climate Risk in May

Flood exposure in May is meaningful by NFIP measures — 1 claim on record and 100% of ZIP codes carrying FEMA flood zone designations. That level of activity makes flood history a relevant factor when evaluating local water quality over time.

1
Total FEMA Flood Claims
$43,083
Avg Claim Payout
100%
ZIPs in FEMA Flood Zones

May has a moderate flood history with 1 FEMA claims averaging $43,083 per payout. 100% of ZIP codes fall within FEMA flood zones. Flood events can contaminate drinking water and overwhelm treatment systems.

How flooding affects water quality: Flood events can introduce sewage, agricultural runoff, and industrial chemicals into water supplies. Even after floodwaters recede, contamination can persist in wells and aging infrastructure. Flood damage can add significantly to the estimated <strong>$3,000</strong> remediation cost per household.

Residents in flood-prone areas should consider flood insurance even outside FEMA zones — over 25% of flood claims come from low-to-moderate risk areas. After any flood event, test your water before drinking.

Source: FEMA National Flood Insurance Program (NFIP) claims data, FEMA flood zone designations.

What You Can Do in May

  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. An NSF-certified pitcher or under-sink filter removes most common contaminants.
  3. Check your home's plumbing. With 63% of homes built before 1986, lead solder is a real possibility.
  4. Review your water system's CCR. Your utility publishes an annual Consumer Confidence Report with detailed test results. Request it or find it online.

Frequently Asked Questions

Is the water safe to drink in May, ID?
May has an average water safety score of 53/100 (Grade D). No EPA violations on record. Check individual ZIP code reports for details specific to your neighborhood.
How does May compare to Idaho average?
May has an average water safety score of 53/100, which is below the Idaho state average of 66/100.
How many water systems serve May?
May is served by 1 public water system across 1 ZIP code, serving approximately 98 people.
How much does it cost to fix water issues in May?
Estimated remediation costs in May average $3,000 per household, ranging from $2,000 to $4,000. Costs include filtration, pipe replacement, radon mitigation, and flood protection.
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