Knightsen, CA Water Safety: 63/100 (2026)
1 ZIP code · 2 water systems · Updated 2026-06-03
In recent monitoring cycles, Knightsen tap water shows a mixed record for CA — several systems have documented violations alongside areas with clean compliance histories.
How Knightsen Compares
Data: EPA SDWIS Last verified: 2026-06-03
Knightsen Water: The Quick Version
- Homes built before 1986: 45% — older plumbing may contain lead solder.
- Estimated remediation: $1,600 per household.
- CDC health risk index: 10.72.
Water Systems Serving Knightsen
Multiple utilities divide Knightsen, CA's water service — 2 leading providers among 2 on the federal register.
Overview
We track water quality and home safety data for 1 ZIP code in Knightsen, California (population ~637), covering 2 community water systems serving approximately 241,357 people region-wide.
No EPA violations recorded across any ZIP codes in Knightsen — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Knightsen: C (63/100)
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
Knightsen water systems draw from: Surface water.
Lead & Copper
- Lead data: not yet available for Knightsen
- 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 |
|---|---|---|---|
| 94548 | C | DIABLO WATER DISTRICT | 43,357 |
All ZIP Codes in Knightsen
- 94548 [C]
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.
CDC Health Data for Knightsen
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
How Old Is Knightsen's Housing Stock?
With 45% 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
When trying to understand water quality at the household level, the year a home was built often matters more than any city-wide water report. That's because the 1986 federal ban on lead solder in plumbing, and the earlier phase-out of lead pipes before 1970, created sharp discontinuities in residential plumbing risk by construction era. Knightsen's median build year of 1997 puts the city in the transition zone: a substantial share of the housing stock postdates the solder ban, but a comparable fraction predates it — with the oldest homes carrying both the solder risk and the pipe risk simultaneously. Whether any individual household sits on the safer or riskier side of these thresholds is the key question, and it's one the city-wide median alone can't answer.
Most homes in Knightsen 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.
Knightsen: Remediation Cost in Perspective
Because property values in Knightsen comfortably exceed estimated remediation costs, the equity impact here is proportionally small.
Remediation costs in Knightsen are relatively low compared to home values. The $800–$2,600 estimated range is a small fraction of median property value. Home values are 24% above the California average.
Protecting Children from Lead in Knightsen
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.
Older interior plumbing shapes the local picture: 45% of Knightsen homes predate the federal solder ban, and aggregate sampling either approaches or crosses the action benchmark. That mix makes a single-home draw a standard pre-purchase or pre-occupancy step.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Climate-Related Water Risk for Knightsen
How does Knightsen's flood record connect to local water quality? The NFIP documents 2 claims — enough to signal recurring events — and 100% of ZIP codes carry FEMA flood zone status. That combination places flooding in the category of factors that can periodically affect water infrastructure, even if the area isn't among the highest-exposure communities in the NFIP dataset.
Knightsen has a moderate flood history with 2 FEMA claims averaging $17,647 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>$1,600</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 Knightsen
- 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 45% of homes built before 1986, lead solder is a real possibility.
Deep Dive Reports
Detailed analysis for Knightsen, CA