City of Westminster
EPA ID: CO0101170 · 202,078 people served · 13 ZIP codes
Beyond the 12 historical violations on City of Westminster's EPA record, nothing remains open — the utility is currently compliant and supplies water to 202,078 residents.
Data: EPA SDWIS Last verified: 2026-04-02
Compliance Trajectory
Worsening · Risk tier: High · 95% chance of violation in next 12 months
Violations went from 2 (2021) to 4 (2024). The pattern suggests growing compliance challenges.
Service Area Map
Coverage area for City of Westminster Source: EPA SDWIS service area boundaries.
Service area boundary — Grade C
Service Area Demographics
The City of Westminster serves a community with a median household income of $105,645 and an estimated 355,838 residents across its service area. Approximately 49% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
🌊 Where Does Your Water Come From?
City of Westminster's water is drawn from rivers, lakes, or reservoirs. Surface water sources are more exposed to agricultural runoff, stormwater, and upstream discharges, but they typically receive more intensive treatment before reaching your tap.
About 1% of homes in Jefferson County, Colorado rely on private wells rather than public water systems. Private well owners are responsible for their own water testing and treatment.
Superfund Proximity Note: This service area ranks in the 68th percentile nationally for proximity to Superfund (NPL) sites.
Infrastructure Risk
Detected Contaminants
How City of Westminster compares to EPA limits
What This Means For You
Contaminant 1006 at 1 mg/L exceeds the EPA maximum of 0.006 mg/L. Cholesterol & blood sugar effects, liver damage. Consider reverse osmosis filtration.
E. coli at 4 Zero tolerance (any positive sample triggers immediate action) exceeds the EPA maximum of Zero tolerance (any positive sample triggers immediate action). Severe GI illness; potentially fatal kidney failure in children. Consider UV disinfection (99.99%) filtration.
Lead and Copper Rule at 3 mg/L exceeds the EPA maximum of mg/L.
Total Organic Carbon at 1 mg/L exceeds the EPA maximum of mg/L.
Total Coliform at 1 presence exceeds the EPA maximum of presence.
PFAS Detected in Service Area
PFAS ("forever chemicals") have been detected in water serving this system's area. 24 detections recorded. 6 exceed federal EPA limits (4 ppt for PFOA/PFOS).
Contaminant 1006 was detected in this water system. reverse osmosis filtration can reduce exposure.
Find a certified water filter →Comparable Water Systems
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Estimated Remediation Costs
Average estimated costs across ZIP codes served by this system
Based on national averages for common remediation projects. Actual costs vary by property. Only issues flagged by EPA, FEMA, or state data for each ZIP code are included.
System Overview
City of Westminster (EPA ID: CO0101170) is a community water system in Colorado that serves approximately 202,078 people from surface water sources.
This system provides water to 13 ZIP codes across 4 communities.
Average Home Safety Score: C (66/100)
Based on water quality violations, lead levels, and radon risk across all ZIP codes served by this system.
Violation History
Recent Violations
| Date | Contaminant | Type | Status |
|---|---|---|---|
| May 1, 2025 | E. coli | Monitoring | Resolved |
| April 1, 2025 | Contaminant 1006 | Monitoring | Resolved |
| January 1, 2025 | E. coli | Monitoring | Resolved |
| December 1, 2024 | E. coli | Monitoring | Resolved |
| April 4, 2024 | Lead and Copper Rule | Monitoring | Resolved |
| March 1, 2024 | Chlorine residual | Health-based | Resolved |
| December 27, 2023 | Lead and Copper Rule | Monitoring | Resolved |
| June 25, 2023 | Total Coliform | Monitoring | Resolved |
| April 1, 2023 | Revised Total Coliform Rule | Monitoring | Resolved |
Contaminants Detected
The following contaminants have been flagged in EPA records for this water system:
| Contaminant | Category | Violations | Health-Based |
|---|---|---|---|
| E. coli | Microbiological | 4 | No |
| Lead and Copper Rule | Treatment Failure | 3 | No |
| Contaminant 1006 | Other Violation | 1 | No |
| Total Organic Carbon | Disinfection Byproducts | 1 | No |
| Total Coliform | Microbiological | 1 | No |
| Revised Total Coliform Rule | Microbiological | 1 | No |
| Chlorine residual | Disinfectant | 1 | Yes |
Health Risk Details
Chlorine (Residual Disinfectant) (EPA limit: 4 mg/L (MRDL — Maximum Residual Disinfectant Level))
Irritation & DBP formation at high levels; protective at normal treatment levels At-risk groups: people with asthma or chemical sensitivities, kidney dialysis patients (water must be dechlorinated).
Removal methods: granular activated carbon (GAC), KDF media filter, carbon block filter. Find the right filter →
Lead & Copper
EPA Lead and Copper Rule sampling data for ZIP codes served by this system:
| ZIP Code | Lead Level | Exceeds Limit | Sample Date |
|---|---|---|---|
| 80030 | 0.0013 mg/L | No | N/A |
| 80031 | 0.0013 mg/L | No | N/A |
| 80035 | 0.0013 mg/L | No | N/A |
| 80036 | 0.0013 mg/L | No | N/A |
Radon Risk in Service Area
Dominant radon zone for ZIP codes served by this system: Zone 1 (High Risk)
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Need help with your water quality?
Typical cost: Water test: typically $20–$50 (DIY kit) · Professional inspection: $150–$400
Find the Right Water FilterFree tip: Let cold water run for 2 minutes before drinking — this helps flush lead from your pipes.
ZIP Codes Served
Coverage: 11 ZIP codes confirmed via EPA Community Water System Service Area Boundaries v3 plus 2 additional ZIPs inferred from SDWIS registry data. The EPA-confirmed set is the most reliable; SDWIS-inferred entries may be narrower than the real deployment area.
- 80003 — Arvada
- 80005 — Arvada
- 80007 — Arvada
- 80020 — Broomfield
- 80021 — Broomfield
- 80023 — Broomfield
- 80030 — Westminster
- 80031 — Westminster
- 80035 — Westminster
- 80036 — Westminster
- 80221 — Denver
- 80234 — Denver
- 80260 — Denver
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for City of Westminster (CO0101170) on EPA.gov.
Frequently Asked Questions
Is City of Westminster water safe to drink?
City of Westminster has recorded 1 health-based violation in the past 5 years. While the system is required to treat water to meet federal standards, you may want to consider additional precautions such as a certified water filter.
How many people does City of Westminster serve?
City of Westminster serves approximately 202,078 people across 13 ZIP codes in Colorado.
Where does City of Westminster get its water?
The primary water source is surface water.
Federal UCMR5 PFAS Monitoring: Tested Clean
This water system was tested under the federal EPA Unregulated Contaminant Monitoring Rule (UCMR5). No PFAS compounds were detected.
Current MCL reflects the lowest state-enforceable limit (NYS 10 ppt for PFOA/PFOS, effective August 2020). The federal final MCL of 4 ppt for PFOA/PFOS (EPA April 2024 rule) is not enforceable until April 2029. Detections above 4 ppt but below 10 ppt are below current MCL but above the future federal limit.
Source: U.S. EPA UCMR5 (Unregulated Contaminant Monitoring Rule, 5th cycle) — per-system federal sampling, 2023–2025. EPA UCMR5 monitoring program →
Lead Service Line Inventory
Service line breakdown reported under the federal Lead and Copper Rule Improvements (LCRI) inventory requirement:
Federal LCRI rule (effective October 2024) requires every public water system to inventory its service lines and complete lead-line replacement within 10 years.
Source: EPA SDWIS Federal Service Line Inventory (Phase 2) · Submitted 2026
ZipCheckup is not affiliated with the utility or state agency. Inventory figures render verbatim from the public LCRI submission cited above; ZipCheckup does not perform inspections or replacements.
How Water Systems Appear in Rankings
Water systems are evaluated by violation history, contaminant detections, and service population. Larger systems with more service connections appear in more rankings.
- #21 / 50 Highest Exposure Burden (Colorado)
Frequently Asked Questions
What You Can Do
Test your water
Home test kits can detect lead, bacteria, and other contaminants at your tap. Find the right filter →
Check your specific ZIP code
Water quality can vary within a system. View nearest ZIP report →
Contact your utility
City of Westminster (EPA ID: CO0101170) — request the latest Consumer Confidence Report or ask about specific contaminants.