TapSafetyReport
C58/100

Castle Rock Tap Water Quality: Is It Safe to Drink? (2026 Report)

Serving 112,478 residents · Colorado

What's In Castle Rock's Tap Water?

69
Contaminants Tested
0
Exceed EPA Limits
2
Above EPA Goals
2 contaminants above EPA health goals
ContaminantDetectedLimit (MCL)Status
chlorate
340.00 µg/L—Above Goal
Lead (90th percentile)
0.002 mg/L0.015 mg/LAbove Goal

EPA Violation History

8

Violations (last 5yr)

0

Unresolved

0

Health-Related

TIER 3Resolved

Failed to complete routine monitoring

This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.

When: June 1, 2025 – June 30, 2025Rule: Surface Water Treatment RuleEnforcement: Resolving — corrective action underway
TIER 3Resolved

Failed to complete routine monitoring

This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.

When: May 1, 2025 – May 31, 2025Rule: Surface Water Treatment RuleEnforcement: Resolving — corrective action underway
TIER 3Resolved

Exceeded the MCL for disinfection byproducts

This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.

When: April 1, 2022 – June 30, 2022Enforcement: Resolving — corrective action underway
TIER 3Resolved

Exceeded the MCL for disinfection byproducts

This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.

When: April 1, 2022 – June 30, 2022Enforcement: Resolving — corrective action underway
TIER 3Resolved

Exceeded the MCL for disinfection byproducts

This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.

When: April 1, 2022 – June 30, 2022Enforcement: Resolving — corrective action underway
TIER 3Resolved

Exceeded the MCL for disinfection byproducts

This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.

When: April 1, 2022 – June 30, 2022Enforcement: Resolving — corrective action underway
TIER 3Resolved

Exceeded the MCL for disinfection byproducts

This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.

When: April 1, 2022 – June 30, 2022Enforcement: Resolving — corrective action underway
TIER 3Resolved

Exceeded the MCL for disinfection byproducts

This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.

When: April 1, 2022 – June 30, 2022Enforcement: Resolving — corrective action underway

Understanding violation severity

Tier 1Urgent health risk. Utility must notify all customers within 24 hours.Tier 2Important health or treatment issue. Customers notified within 30 days.Tier 3Administrative or monitoring issue. Reported in the annual water quality report.

Source: EPA Safe Drinking Water Information System (SDWIS) · Updated quarterly

Water Utility Details

CASTLE PINES VILLAGE MD
Population Served

5,656

Water Source

Groundwater

System ID

CO0118005

CASTLE ROCK TOWN OF
Population Served

106,822

Water Source

Surface Water

System ID

CO0118010

Frequently Asked Questions About Castle Rock Water

Is Castle Rock tap water safe to drink?

Castle Rock, Colorado tap water receives a grade of C (58/100), which is considered fair. 0 contaminant(s) exceed EPA maximum contaminant levels and 75 violation(s) are on record. Residents should consider using an NSF-certified water filter to reduce contaminant exposure.

What contaminants are in Castle Rock's water?

Of the 72 contaminants tested in Castle Rock's water supply, the most notable include Lead (90th percentile), chlorate. No contaminants exceed EPA legal limits. 2 contaminant(s) exceed EPA health goals (MCLGs), which are non-enforceable targets set at levels with no known health risk.

Does Castle Rock have any water quality violations?

Yes, Castle Rock has 75 EPA violation(s) on record, with the most recent in 2025. Violation types include MR, Other. None of these are classified as health-based violations.

Do I need a water filter in Castle Rock?

Castle Rock water meets EPA standards, so a filter is not strictly necessary. However, some residents prefer the added security of a water filter. EPA health goals (MCLGs) are stricter than legal limits and are set at levels with zero expected health risk. 2 contaminant(s) exceed these stricter goals.

Where does Castle Rock's tap water come from?

Castle Rock's drinking water is sourced from groundwater and supplied by CASTLE PINES VILLAGE MD and 1 other water system(s). The system serves approximately 112,478 people. Groundwater is pumped from underground aquifers, which often provides natural filtration.

How often is Castle Rock's water tested?

Under the Safe Drinking Water Act (SDWA), water utilities are required to regularly test for over 90 contaminants. Testing frequency varies by contaminant — some are tested monthly, others quarterly or annually. Castle Rock's water systems must report results to the EPA and publish an annual Consumer Confidence Report (CCR). The data on this page reflects the latest available EPA testing data.

How does Castle Rock's water compare to other cities in Colorado?

Castle Rock's water quality score of 58/100 earns a grade of C, which is considered fair. This is a below-average score that indicates room for improvement. Visit our Colorado state page to see how all cities in the state compare.

What should I do if I'm concerned about Castle Rock's water quality?

If you have concerns about Castle Rock's tap water, consider these steps: (1) Request your utility's annual Consumer Confidence Report for detailed local data. (2) Get your water independently tested through a state-certified laboratory. (3) Consider an NSF-certified water filter rated for the contaminants found in your area. (4) Contact your water utility (CASTLE PINES VILLAGE MD) with specific questions. (5) Report water quality issues to your state drinking water program or the EPA Safe Drinking Water Hotline at 800-426-4791.

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