Water Quality in Boulder, CO: 110 Violations - Grade N/A
14 water systems · 6 directly mapped ZIP records
Available EPA records report 110 violations across 6 directly mapped ZIP records with known counts for Boulder. This is compliance evidence, not a property-level tap-water verdict.
Data: EPA Safe Drinking Water Information System (SDWIS)
Water Quality by ZIP Code in Boulder
This table shows typed EPA water evidence only. Missing violation counts are displayed as N/A, not zero.
| ZIP Code | Violations | Health | |
|---|---|---|---|
| 80301 | 82 | 4 | View report → |
| 80305 | 19 | 11 | View report → |
| 80303 | 17 | 3 | View report → |
| 80302 | 3 | 0 | View report → |
| 80304 | 3 | 0 | View report → |
| 80310 | 2 | 0 | View report → |
Violation Trend
EPA violations recorded for water systems serving Boulder.
| Year | Total violations | Health-based |
|---|---|---|
| 2021 | 10 | 10 |
| 2022 | 3 | 3 |
| 2023 | 2 | 2 |
| 2024 | 1 | 1 |
| 2025 | 1 | 1 |
Water Quality Overview
Boulder, Colorado has directly mapped EPA water-system data for 6 ZIP codes. This page reports typed compliance facts and does not relabel the multi-source Home Safety Score as a drinking-water grade.
The available EPA records report 110 violations, including 18 health-based violations across 6 directly mapped ZIP records with reported counts.
Lead Levels
The average 90th percentile lead level across Boulder water systems is 0.0034 mg/L - within EPA limits. No exceedances appear among the 6 ZIP records with known lead status.
With 67% of homes built before 1986, Boulder has a higher-than-average risk of lead from older plumbing. Lead solder was banned in 1986, and homes built before this date may have lead in pipes, solder joints, or fixtures.
Water Systems Serving Boulder
Boulder is served by 14 community water systems regulated under the Safe Drinking Water Act. These systems collectively serve approximately 129,202 people across 16 ZIP codes.
Each water system is identified by a Public Water System ID (PWSID) and is required to:
- Test for over 90 regulated contaminants on a regular schedule
- Report results to the EPA and state regulators
- Issue an annual Consumer Confidence Report (CCR) to all customers
- Take corrective action when violations occur
The EPA has taken 57 enforcement actions against water systems serving Boulder. Enforcement actions range from informal compliance assistance to formal orders and penalties.
How to Check Your Water in Boulder
Enter your ZIP code on ZipCheckup to see your specific water system data, including contaminant levels and violation history
Request your CCR - your water utility must provide an annual Consumer Confidence Report with detailed test results for all monitored contaminants
Get a home test - certified kits cost $20–$50 and test for lead, bacteria, and common contaminants. Professional lab tests ($150–$400) cover a broader panel
Consider filtration - NSF-certified filters can remove specific contaminants. Reverse osmosis removes the broadest range; activated carbon is effective for chlorine and many organics
Check for advisories - monitor your local utility website and local news for boil water advisories or system alerts
Contaminants Detected in Boulder Water Systems
The following contaminants have been detected or caused violations across Boulder's water systems:
| Contaminant | Category | MCL | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|---|
| E. coli | Microbiological | N/A | 39 | 6 | Yes |
| Fecal Coliform | Microbiological | N/A | 24 | 6 | Yes |
| Lead and Copper Rule | Treatment Technique | N/A | 10 | 1 | No |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 0.08 mg/L | 7 | 2 | No |
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 0.06 mg/L | 7 | 2 | No |
| Surface Water Treatment Rule | Treatment Technique | N/A | 6 | 4 | No |
| Chlorine residual | Disinfectant | 4 mg/L | 2 | 1 | Yes |
| Revised Total Coliform Rule | Microbiological | N/A | 2 | 2 | No |
| PFOA | PFAS | 0.000004 mg/L | 1 | 1 | No |
| PFNA | PFAS | 0.00001 mg/L | 1 | 1 | No |
| Chlorite | Disinfection Byproducts | 1 mg/L | 1 | 1 | No |
| Monochloroacetic Acid | Disinfection Byproducts | 0.06 mg/L | 1 | 1 | No |
| Dichloroacetic Acid | Disinfection Byproducts | 0.06 mg/L | 1 | 1 | No |
| Bromodichloromethane | Disinfection Byproducts | 0.08 mg/L | 1 | 1 | No |
| Dibromochloromethane | Disinfection Byproducts | 0.08 mg/L | 1 | 1 | No |
MCL = Maximum Contaminant Level (EPA enforceable standard). Health-based violations indicate levels that may pose direct health risks.
Violation Trend Over Time
Year-by-year EPA violations recorded for water systems serving Boulder:
| Year | Total Violations | Health-Based |
|---|---|---|
| 2021 | 10 | 10 |
| 2022 | 3 | 3 |
| 2023 | 2 | 2 |
| 2024 | 1 | 1 |
| 2025 | 1 | 1 |
Violations have decreased from 10 in 2021 to 1 in 2025, indicating improving compliance.
EPA Enforcement History
The EPA and state regulators have taken 43 enforcement actions against water systems serving Boulder. Recent actions:
| Date | Action Type |
|---|---|
| 2026-03-30 | State Informal Action |
| 2026-03-30 | State Filed Suit |
| 2026-03-12 | State Informal Action |
| 2026-03-12 | State Informal Enforcement |
| 2026-03-11 | State Order Extension |
| 2026-02-20 | State Order Extension |
| 2026-01-16 | State Informal Action |
| 2026-01-16 | State Informal Enforcement |
| 2026-01-16 | State Order Extension |
| 2025-12-15 | State Informal Action |
Enforcement actions range from informal compliance assistance to formal orders and penalties. The most recent action was on 2026-03-30.
Boulder vs. Nearby Colorado Cities
How Boulder's water quality compares to similar cities in Colorado:
| City | Direct EPA ZIPs | Violations | Systems | Population |
|---|---|---|---|---|
| Boulder | 6 | 110 | 14 | 129,202 |
| Arvada | 5 | 9 | 8 | 138,109 |
| Greeley | 2 | 28 | 7 | 117,473 |
| Longmont | 3 | 19 | 8 | 141,102 |
Water Quality by ZIP Code in Boulder
EPA coverage and recorded violations can differ across Boulder's ZIP codes. Missing counts are shown as unavailable, not zero:
Common Questions About Boulder Water
These are the most common questions residents search for about water quality in Boulder, Colorado:
Is Boulder water hard or soft? Water hardness varies by source. Boulder's 14 water systems use multiple sources. Check your ZIP code report for specific hardness data.
Can I drink Boulder tap water? City-level EPA records cannot determine safety at a specific tap. The measured subset contains 18 health-based violations; check the affected utility record and consider certified testing.
What is the best water filter for Boulder? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
Boulder vs. Colorado Average
Understanding how Boulder compares to the broader Colorado average helps contextualize your local water quality. Factors like water source, treatment methods, and infrastructure age all contribute to differences between cities in the same state.
To see how individual neighborhoods compare, check the ZIP code reports below - water quality can vary significantly even within Boulder.
ZIP Codes in Boulder
Boulder spans 16 ZIP codes. EPA water-system coverage is available for 6 directly mapped ZIP codes. Check each ZIP code for detailed contaminant data, violation history, and system information.
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
- Enforcement: EPA ECHO database
- Filter recommendations: NSF/ANSI certified products
Source reporting periods vary. See each cited source for its publication schedule.