Nampa, ID: 20 Violations — 77/100 (2026)
5 ZIP codes · 10 water systems · Updated 2026-06-03
Unlike many cities its size in ID, Nampa keeps health-based violation rates low — systems here score at or above the state average for tap water safety, with no systemic concerns flagged in the current data set.
How Nampa Compares
Data: EPA SDWIS Last verified: 2026-06-03
Water Quality Map: Nampa, ID
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Score Distribution
How ZIP codes in Nampa score across all safety grades.
What You Should Know About Nampa Water
- Your city's water systems recorded 20 violations in the past 5 years.
- Average lead level: 0.002 mg/L.
- Homes built before 1986: 36% — older plumbing may contain lead solder.
- Estimated remediation: $1,120 per household.
- CDC health risk index: 12.08 — above typical levels.
Who Supplies Your Water in Nampa
3 water utilities share the residential service territory in Nampa, ID — out of 10 total systems in federal records.
Overview
We track water quality and home safety data for 5 ZIP codes in Nampa, Idaho (population ~136,828), covering 10 community water systems serving approximately 355,377 people region-wide.
5 of 5 ZIP codes (100%) have recorded EPA violations. All violations are monitoring/reporting type.
Home Safety Score
Average Home Safety Score for Nampa: B (77/100)
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
Nampa water systems draw from: Groundwater.
Lead & Copper
- Average lead level (90th percentile): 0.0020 mg/L (EPA action level: 0.015 mg/L)
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 2 (Moderate Risk)
- Zone 1 (High): 0 ZIP codes
- Zone 2 (Moderate): 5 ZIP codes
- Zone 3 (Low): 0 ZIP codes
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Top Contaminants
| Contaminant | Category | Violations | ZIPs Affected |
|---|---|---|---|
| Atrazine | Organic | 6 | 5 |
| Combined Radium | Radionuclides | 6 | 5 |
| Consumer Confidence Report Rule | Reporting | 6 | 5 |
| Revised Total Coliform Rule | Microbiological | 6 | 5 |
Areas with Most Violations
| ZIP Code | Safety Score | Violations | Health-Based | System |
|---|---|---|---|---|
| 83651 | B | 4 | 0 | City of Nampa |
| 83652 | B | 4 | 0 | City of Nampa |
| 83653 | B | 4 | 0 | City of Nampa |
| 83686 | B | 4 | 0 | City of Nampa |
| 83687 | B | 4 | 0 | City of Nampa |
All ZIP Codes in Nampa
- 83651 [B] — 4 violations
- 83652 [B] — 4 violations
- 83653 [B] — 4 violations
- 83686 [B] — 4 violations
- 83687 [B] — 4 violations
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Radon: EPA Map of Radon Zones
Updated daily.
Health Outcomes in Nampa
Source: CDC PLACES (County-level estimates). Water contamination can correlate with respiratory and chronic health conditions.
Compared to National Average
Vertical line = national average. ■ Above national · ■ Below national
Top Contaminants in Nampa Water
Based on EPA violation records. Check your ZIP code report for system-specific contaminant data.
Housing & Infrastructure in Nampa
Housing age data helps assess potential lead pipe and infrastructure risks. Newer housing stock generally means lower plumbing-related contamination risk.
Source: U.S. Census Bureau American Community Survey (ACS).
Housing Age Profile
Development in Nampa unfolded across multiple decades, and the median build year of 1988 reflects a housing inventory where eras of construction are genuinely mixed — including portions that predate the federal prohibition on lead solder in plumbing.
Most homes in Nampa were built after 1986, reducing the risk of lead contamination from plumbing. Older homes should still be tested.
Source: U.S. Census Bureau ACS B25034.
Cost Context: What Remediation Means for Nampa Homeowners
Property equity in Nampa runs well ahead of estimated remediation costs — a cost-to-value ratio that sits in the low tier, meaning documented water and safety issues here are the kind homeowners can plan to address without treating the expense as a significant budget event relative to what their homes are worth.
Remediation costs in Nampa are relatively low compared to home values. The $480–$1,880 estimated range is a small fraction of median property value. Home values are 11% above the Idaho average.
Lead Exposure Risk for Children in Nampa
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.
Locally, 36% of Nampa homes carry interior plumbing from the era when lead solder was still permitted in new builds, and citywide monitoring approaches or crosses the EPA action benchmark. Households can find a draw-test kit and certified filtration through verified retailers.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Flood & Climate Risk in Nampa
Nampa's flood exposure sits in the moderate range: 9 NFIP claims on record and 40% of ZIP codes within FEMA-designated flood zones. Residents with private wells or older infrastructure have reasonable grounds to factor flood timing into their water quality awareness.
Nampa has a moderate flood history with 9 FEMA claims averaging $2,591 per payout. 40% 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>$1,120</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.
Deep Dive Reports
Detailed analysis for Nampa, ID