Little Thompson Water District
EPA ID: CO0135477 · 25,654 people served · 13 ZIP codes
Federal compliance records for Little Thompson Water District list 2 open violations that have not yet been resolved — the utility serves approximately 25,654 people, and each outstanding finding remains logged and active in the EPA enforcement database.
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 5 (2021) to 8 (2025). The pattern suggests growing compliance challenges.
Service Area Map
Coverage area for Little Thompson Water District Source: EPA SDWIS service area boundaries.
Service area boundary — Grade D
Service Area Demographics
The Little Thompson Water District serves a community with a median household income of $109,671 and an estimated 423,771 residents across its service area.
🌊 Where Does Your Water Come From?
Little Thompson Water District'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.
Infrastructure Risk
Detected Contaminants
How Little Thompson Water District compares to EPA limits
What This Means For You
Consumer Confidence Report Rule at 3 mg/L exceeds the EPA maximum of mg/L.
E. coli at 3 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.
Revised Total Coliform Rule 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. 10 detections recorded. 10 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
Little Thompson Water District (EPA ID: CO0135477) is a community water system in Colorado that serves approximately 25,654 people from surface water sources.
This system provides water to 13 ZIP codes across 10 communities.
Average Home Safety Score: D (52/100)
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, 2024 | Consumer Confidence Report Rule | Monitoring | Resolved |
Contaminants Detected
The following contaminants have been flagged in EPA records for this water system:
| Contaminant | Category | Violations | Health-Based |
|---|---|---|---|
| Consumer Confidence Report Rule | Reporting Failure | 3 | No |
| E. coli | Microbiological | 3 | No |
| Fecal Coliform | Microbiological | 1 | No |
| Revised Total Coliform Rule | Microbiological | 1 | No |
Lead & Copper
EPA Lead and Copper Rule sampling data for ZIP codes served by this system:
| ZIP Code | Lead Level | Exceeds Limit | Sample Date |
|---|---|---|---|
| 80513 | 0.01 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: Service area ZIP codes sourced from EPA Community Water System Service Area Boundaries v3 (March 2026 release). These ZIPs reflect the actual deployment footprint recorded by CO or modeled from parcel and building-footprint data.
- 80503 — Longmont
- 80504 — Longmont
- 80513 — Berthoud
- 80526 — Fort Collins
- 80528 — Fort Collins
- 80534 — Johnstown
- 80537 — Loveland
- 80538 — Loveland
- 80542 — Mead
- 80543 — Milliken
- 80550 — Windsor
- 80634 — Greeley
- 80651 — Platteville
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for Little Thompson Water District (CO0135477) on EPA.gov.
Frequently Asked Questions
Is Little Thompson Water District water safe to drink?
Little Thompson Water District has only monitoring/reporting violations, which are procedural in nature. The system meets federal health-based standards.
How many people does Little Thompson Water District serve?
Little Thompson Water District serves approximately 25,654 people across 13 ZIP codes in Colorado.
Where does Little Thompson Water District 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 LITTLE THOMPSON WD 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: LITTLE THOMPSON WD Consumer Confidence Report.
ZipCheckup is not affiliated with this water utility. Treatment and source data are sourced from the utility's published CCR filings.
Treatment regime
How this utility classifies its treatment process and what each reported treatment chemical does.
Watershed exposure sources reported
Land-use and natural conditions identified in the utility's source-water assessment as potential contamination sources upstream of treatment.
Treatment classification and chemical list sourced from LITTLE THOMPSON WD 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: Detected
This water system was tested under the federal EPA Unregulated Contaminant Monitoring Rule (UCMR5). PFAS compounds were detected below the current state-enforceable MCL.
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 →
PFAS Substances Detected in This System
This water system's Consumer Confidence Report disclosed the following PFAS compounds. Levels are from the utility's most recent reporting cycle.
In April 2024, EPA finalized the first National Primary Drinking Water Regulation for six PFAS. Public water systems have until 2029 to comply. EPA — PFAS regulation overview →
Source: Consumer Confidence Report disclosed by LITTLE THOMPSON WD.
ZipCheckup is not affiliated with this water utility. PFAS detection data is sourced from public Consumer Confidence Reports filed by the utility itself.
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.
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
Little Thompson Water District (EPA ID: CO0135477) — request the latest Consumer Confidence Report or ask about specific contaminants.