Thornton, WA Water Safety: 53/100 (2026)
1 ZIP code · 1 water system · Updated 2026-06-03
Within Thornton, water quality data indicates below-average safety by WA standards — independent testing is a reasonable precaution for residents whose systems show active violations.
How Thornton Compares
Data: EPA SDWIS Last verified: 2026-06-03
Key Facts for Thornton Residents
- Homes built before 1986: 86% — older plumbing may contain lead solder.
- Estimated remediation: $400 per household.
- CDC health risk index: 9.94.
Thornton's Water Providers
For most households in Thornton, WA, tap water comes from one provider — the utility that controls the local distribution system out of 1 tracked in federal record.
Overview
We track water quality and home safety data for 1 ZIP code in Thornton, Washington (population ~132), covering 1 community water system serving approximately 831 people region-wide.
No EPA violations recorded across any ZIP codes in Thornton — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Thornton: 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
Thornton water systems draw from: Groundwater.
Lead & Copper
- Lead data: not yet available for Thornton
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 2 (Moderate 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 |
|---|---|---|---|
| 99176 | D | ROSALIA TOWN OF | 831 |
All ZIP Codes in Thornton
- 99176 [D]
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.
Thornton Community Health Snapshot
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
Thornton Infrastructure Age
With 86% 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
For residents trying to assess tap water risk in Thornton, the median build year of 1948 is the starting context. It signals that a majority of homes were constructed before 1986 — the year federal rules prohibited lead solder in new plumbing — and that a significant share likely predates 1970, when lead pipes were still a common choice for residential service connections. Neither risk tier is rare in this housing inventory.
Over half of homes in Thornton 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.
How Remediation Costs Compare in Thornton
Within the Thornton market, estimated remediation claims a small portion of typical property equity — the financial burden is proportionally low.
Remediation costs in Thornton are relatively low compared to home values. The $0–$800 estimated range is a small fraction of median property value. Home values are 45% below the Washington average.
Thornton: Lead Risk & Vulnerable Populations
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.
Before the federal solder ban, lead solder was a routine plumbing material, and 86% of the Thornton inventory was built in that earlier era — a share large enough to move household-level reads onto the standard list.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
What You Can Do in Thornton
- 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.
- Install a certified water filter. An NSF-certified pitcher or under-sink filter removes most common contaminants.
- Check your home's plumbing. With 86% of homes built before 1986, lead solder is a real possibility.
- Review your water system's CCR. Your utility publishes an annual Consumer Confidence Report with detailed test results. Request it or find it online.
Deep Dive Reports
Detailed analysis for Thornton, WA