Sonora, CA: 1 Violation — 70/100 (2026)
1 ZIP code · 8 water systems · Updated 2026-06-03
In current tracking cycles, Sonora records above-average water quality outcomes for CA; compliance history over recent years shows few departures from federal standards and no systemic failures across its water systems.
How Sonora Compares
Data: EPA SDWIS Last verified: 2026-06-03
Key Facts for Sonora Residents
- Your city's water systems recorded 1 violation in the past 5 years.
- Average lead level: 0.0081 mg/L.
- Homes built before 1986: 66% — older plumbing may contain lead solder.
- Estimated remediation: $2,100 per household.
- CDC health risk index: 13.17 — above typical levels.
Sonora's Water Providers
3 water utilities share the residential service territory in Sonora, CA — out of 8 total systems in federal records.
Overview
We track water quality and home safety data for 1 ZIP code in Sonora, California, covering 8 community water systems serving approximately 28,373 people.
1 of 1 ZIP code (100%) have recorded EPA violations. All violations are monitoring/reporting type.
Home Safety Score
Average Home Safety Score for Sonora: B (70/100)
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
Sonora water systems draw from: Groundwater, Surface water.
Lead & Copper
- Average lead level (90th percentile): 0.0081 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)
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Top Contaminants
| Contaminant | Category | Violations | ZIPs Affected |
|---|---|---|---|
| Consumer Confidence Report Rule | Reporting | 2 | 1 |
Areas with Most Violations
| ZIP Code | Safety Score | Violations | Health-Based | System |
|---|---|---|---|---|
| 95370 | B | 1 | 0 | Tud - Upper Basin Water System |
All ZIP Codes in Sonora
- 95370 [B] — 1 violation
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.
Sonora 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
What's in Sonora's Water?
Based on EPA violation records. Check your ZIP code report for system-specific contaminant data.
Sonora Infrastructure Age
With 66% 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
Two dates define the high-risk tiers of residential plumbing from a lead standpoint: 1970, before which lead pipes were commonly installed for service connections, and 1986, before which lead solder was standard in copper plumbing. A median build year of 1971 places Sonora's housing distribution well within that older risk zone. The bar chart above breaks down how much of the stock falls into each era — and the pre-1986 share alone represents more than half the residential inventory, making plumbing-era risk a defining characteristic of the local water safety picture.
Over half of homes in Sonora 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 Sonora
Low proportionality — that's the Sonora picture when remediation costs are placed against typical home equity.
Remediation costs in Sonora are relatively low compared to home values. The $1,100–$3,400 estimated range is a small fraction of median property value. Home values are 44% below the California average.
Sonora: 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.
Wherever 66% of local housing was built before solder rules changed — as is the case in Sonora — a faucet-level sample closes the gap that aggregate utility data cannot.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Sonora: Flood History & Water Damage Risk
A moderate NFIP record for Sonora — 14 insurance claims paired with 100% of ZIP codes in FEMA flood zones — points to a flood history where water-quality pathways have likely been periodically relevant.
Sonora has a moderate flood history with 14 FEMA claims averaging $14,640 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>$2,100</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 Sonora, CA