Descanso, CA Water Safety: 66/100 (2026)
1 ZIP code · 1 water system · Updated 2026-06-03
In recent monitoring cycles, Descanso tap water shows a mixed record for CA — several systems have documented violations alongside areas with clean compliance histories.
How Descanso Compares
Data: EPA SDWIS Last verified: 2026-06-03
Descanso Water: The Quick Version
- Homes built before 1986: 59% — older plumbing may contain lead solder.
- CDC health risk index: 10.18.
Water Systems Serving Descanso
In Descanso, CA, the drinking water supply is organized under a single dominant utility — a consolidated structure that shapes how infrastructure investment, regulatory compliance, and rate decisions flow to households. When one provider handles the overwhelming share of residential connections out of 1 tracked system, accountability is clear: service upgrades, EPA violation responses, and tariff changes all funnel through that single organizational structure.
Overview
We track water quality and home safety data for 1 ZIP code in Descanso, California, covering 1 community water system serving approximately 1,757 people.
No EPA violations recorded across any ZIP codes in Descanso — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Descanso: C (66/100)
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
Descanso water systems draw from: Groundwater.
Lead & Copper
- Lead data: not yet available for Descanso
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 3 (Low Risk)
Areas with No Violations
| ZIP Code | Safety Score | System | Population |
|---|---|---|---|
| 91916 | C | GUATAY MUTUAL BENEFIT CORPORATION | 100 |
All ZIP Codes in Descanso
- 91916 [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 Descanso
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 Descanso's Housing Stock?
With 59% 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 Descanso, the median build year of 1988 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 Descanso 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.
Protecting Children from Lead in Descanso
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 59% of the Descanso 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.
What You Can Do in Descanso
- 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 59% of homes built before 1986, lead solder is a real possibility.
Deep Dive Reports
Detailed analysis for Descanso, CA