City of Boulder
EPA ID: CO0107152 · 166,080 people served · 19 ZIP codes
Federal data shows 6 unresolved violations at City of Boulder — roughly 166,080 residents in the service area.
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 21 (2021) to 17 (2022). The pattern suggests growing compliance challenges.
Service Area Map
Coverage area for City of Boulder Source: EPA SDWIS service area boundaries.
Service area boundary — Grade C
Service Area Demographics
The City of Boulder serves a community with a median household income of $119,699 and an estimated 199,507 residents across its service area. Approximately 62% 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 Boulder'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 Boulder County, Colorado rely on private wells rather than public water systems. Private well owners are responsible for their own water testing and treatment.
Wastewater Proximity Note: This service area ranks in the 60th percentile nationally for proximity to wastewater discharge points. Surface water sources near wastewater outfalls may face additional treatment challenges.
Superfund Proximity Note: This service area ranks in the 60th percentile nationally for proximity to Superfund (NPL) sites.
Infrastructure Risk
Detected Contaminants
How City of Boulder compares to EPA limits
What This Means For You
Lead and Copper Rule at 6 mg/L exceeds the EPA maximum of mg/L.
Surface Water Treatment Rule at 2 mg/L exceeds the EPA maximum of mg/L.
E. coli at 1 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.
Fecal 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. 9 detections recorded. 3 exceed federal EPA limits (4 ppt for PFOA/PFOS).
E. coli was detected in this water system. UV disinfection (99.99%) filtration can reduce exposure.
Find a certified water filter →Comparable Water Systems
Similar-sized systems in Colorado
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
BOULDER CITY OF (EPA ID: CO0107152) is a community water system in Colorado that serves approximately 166,080 people from surface water sources.
This system provides water to 19 ZIP codes across 4 communities.
Average Home Safety Score: C (61/100)
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 |
|---|---|---|---|
| August 17, 2025 | Lead and Copper Rule | Monitoring | Unresolved |
| July 9, 2025 | Lead and Copper Rule | Monitoring | Unresolved |
| July 1, 2025 | Surface Water Treatment Rule | Monitoring | Unresolved |
| April 9, 2025 | Lead and Copper Rule | Monitoring | Unresolved |
| January 9, 2025 | Lead and Copper Rule | Monitoring | Unresolved |
| October 1, 2024 | Fecal Coliform | Monitoring | Resolved |
Contaminants Detected
The following contaminants have been flagged in EPA records for this water system:
| Contaminant | Category | Violations | Health-Based |
|---|---|---|---|
| Lead and Copper Rule | Treatment Failure | 6 | No |
| Surface Water Treatment Rule | Treatment Failure | 2 | No |
| Chlorine residual | Disinfectant | 2 | Yes |
| E. coli | Microbiological | 1 | No |
| Fecal Coliform | Microbiological | 1 | No |
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 |
|---|---|---|---|
| 80301 | 0.002 mg/L | No | N/A |
| 80302 | 0.002 mg/L | No | N/A |
| 80303 | 0.002 mg/L | No | N/A |
| 80304 | 0.002 mg/L | No | N/A |
| 80305 | 0.002 mg/L | No | N/A |
| 80306 | 0.002 mg/L | No | N/A |
| 80307 | 0.002 mg/L | No | N/A |
| 80308 | 0.002 mg/L | No | N/A |
| 80309 | 0.002 mg/L | No | N/A |
| 80310 | 0.002 mg/L | No | N/A |
| 80314 | 0.002 mg/L | No | N/A |
| 80321 | 0.002 mg/L | No | N/A |
| 80322 | 0.002 mg/L | No | N/A |
| 80323 | 0.002 mg/L | No | N/A |
| 80328 | 0.002 mg/L | No | N/A |
| 80329 | 0.002 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: 9 ZIP codes confirmed via EPA Community Water System Service Area Boundaries v3 plus 10 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.
- 80025 — Eldorado Springs
- 80027 — Louisville
- 80301 — Boulder
- 80302 — Boulder
- 80303 — Boulder
- 80304 — Boulder
- 80305 — Boulder
- 80306 — Boulder
- 80307 — Boulder
- 80308 — Boulder
- 80309 — Boulder
- 80310 — Boulder
- 80314 — Boulder
- 80321 — Boulder
- 80322 — Boulder
- 80323 — Boulder
- 80328 — Boulder
- 80329 — Boulder
- 80503 — Longmont
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for City of Boulder (CO0107152) on EPA.gov.
Frequently Asked Questions
Is City of Boulder water safe to drink?
City of Boulder has recorded 2 health-based violations 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 Boulder serve?
City of Boulder serves approximately 166,080 people across 19 ZIP codes in Colorado.
Where does City of Boulder get its water?
The primary water source is surface water.
Contact Your Water Utility
Public-record contact information for the water utility serving this system. Use these channels to request water quality reports, ask about service, or report issues directly.
Contact information from City of Boulder Consumer Confidence Report.
ZipCheckup is not affiliated with this water utility, does not act as its agent, and does not provide customer support for it. Contact details shown are public-record information from CCR filings. For service issues, contact the utility directly using the information above.
Water Source & Treatment
Where this water originates and how it's treated before reaching your tap.
Source: City of Boulder Consumer Confidence Report.
ZipCheckup is not affiliated with this water utility. Treatment and source data are sourced from the utility's published CCR filings.
The city closely monitors activities that could affect source water and implements an extensive water quality monitoring program from source to tap, including a protection plan. The protection plan identifies potential contaminant sources that could occur, but it does not mean these contaminants do occur.
Treatment regime
How this utility classifies its treatment process and what each reported treatment chemical does.
Treatment chemicals and what each one does
Chemical names are reported verbatim by the utility. Purpose categories are ZipCheckup annotations based on standard drinking-water treatment practice.
Treatment classification and chemical list sourced from City of Boulder Consumer Confidence Report.
Treatment intensity is a ZipCheckup-derived classification based on the chemicals and processes the utility reports. Chemicals and contamination sources are taken verbatim from the utility's CCR filing. Routine federal monitoring and contaminant testing shown elsewhere on this page determine whether the water meets safety standards, not the treatment classification.
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 Replacement Tracker
This water utility's lead service line (LSL) replacement program is tracked from public Consumer Confidence Report filings. Email signup notifies subscribers when the utility files an updated replacement plan or progress milestone.
City of Boulder
ZipCheckup is not affiliated with this water utility. LSL replacement-program data is sourced from public CCR filings published by the utility. Subscription notifications are based on automated parsing of subsequent CCR releases.
Learn more about Lead and Copper Rule replacement requirements →
Lead Service Line Inventory
Service line breakdown reported under the federal Lead and Copper Rule Improvements (LCRI) inventory requirement:
This system reports zero confirmed lead service lines in its inventory. Unknown-material counts may still warrant verification.
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.
Notable events and violations
This section summarizes events the utility chose to disclose in its most recent Consumer Confidence Report, plus any federal compliance violations the utility recorded against itself. Both lists are utility-authored — ZipCheckup does not audit, judge, or reorder them.
Federal compliance violations on record
These entries are taken verbatim from the utility's CCR violations section. EPA defines four broad violation categories: Maximum Contaminant Level (MCL), Treatment Technique (TT), Monitoring & Reporting (M&R), and Public Notification (PN).
-
monitoring · Chlorine2024
On four occasions the chlorine readings differed by greater than allowable margins at different measuring points at the Betasso WTP.
-
monitoring · Turbidity2024
Due to a power outage, turbidity was not analyzed at the 63rd WTP during an 18-hour period.
-
treatment technique · Backflow and Cross-Connection Control2024
Five cross-connections on private properties were uncontrolled for more than 12 months without city staff requesting a compliance extension from the state.
Violations record from City of Boulder Consumer Confidence Report.
ZipCheckup note: items above reflect what the utility published in its most recent CCR. Federal violation records are also tracked separately by the EPA Safe Drinking Water Information System (SDWIS) — the SDWIS record is the authoritative federal source for any specific regulatory action.
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.
- #23 / 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 Boulder (EPA ID: CO0107152) — request the latest Consumer Confidence Report or ask about specific contaminants.