CITY REPORT
CO
Castle Rock, CO Water Quality Report
1 ZIP code · 5 water systems · Updated 2026-03-16
Data: EPA SDWIS Last verified: 2026-03-16
1
ZIP Codes
5
Water Systems
1
ZIPs with Violations
Zone 1
Radon Risk (High)
Overview
We track water quality and home safety data for 1 ZIP code in Castle Rock, Colorado, covering 5 community water systems serving approximately 106,822 people.
1 of 1 ZIP code (100%) have recorded EPA violations. All violations are monitoring/reporting type.
Water Sources
Castle Rock water systems draw from: Groundwater, Surface water.
Lead & Copper
- Lead data: not yet available for Castle Rock
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 1 (High Risk)
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Top Contaminants
| Contaminant | Category | Violations | ZIPs Affected |
|---|---|---|---|
| Gross Alpha | Radionuclides | 16 | 1 |
| Combined Radium | Radionuclides | 16 | 1 |
| Gross Beta | Radionuclides | 16 | 1 |
| E. coli | Microbiological | 8 | 1 |
| Lead and Copper Rule | Treatment Technique | 4 | 1 |
Areas with Most Violations
| ZIP Code | Safety Score | Violations | Health-Based | System |
|---|---|---|---|---|
| 80104 | — | 30 | 0 | CASTLE ROCK TOWN OF |
All ZIP Codes in Castle Rock
- 80104 — 30 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.