Public water system · CO0107487
ActiveLouisville City of
At a glance
City of Louisville (PWSID CO0107487) is an active community water system in Boulder County, Colorado. It reports serving 20,975 people through 7,368 service connections. Its primary water source is surface water, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, 2 are health-based, and the most recent began in October 2024.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
20,975
Service connections
7,368
Primary source
SW
Surface water
System type
CWS
Community water system
System record
How does City of Louisville compare with other water systems in Boulder County?
By EPA's size categories, City of Louisville is a large system (10,001 to 100,000 people). Boulder County has 81 active public water systems, and City of Louisville is the 5th-largest of them by population served. Its population served is about 3.9 times the county average of 5,397 people per system, and accounts for 4.8% of the 437,116 people reported by systems filed under the county. Across Colorado, the 2,207 active systems average 3,400 people each. Nationally, the average active community water system reports serving 6,703 people, so City of Louisville is about 3.1 times that figure.
What does “community water system” mean?
A community water system serves at least 15 connections used by year-round residents, or regularly serves at least 25 year-round residents. Homes, apartments and mobile-home parks are served by these. Colorado has 1,068 active community water systems, 48% of the state's 2,207 active systems. Surface water means the system draws its water from rivers, lakes, streams or reservoirs. 228 Colorado systems (10%) list surface water as their primary source.
Who owns and regulates City of Louisville?
EPA lists City of Louisville as owned by a local government. The CO state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 22 of the 81 active systems in Boulder County (27%) are also owned by a local government.
Does City of Louisville have drinking water violations?
Of the 12 most recent violations in EPA's records, 2 are health-based, and the most recent began in October 2024. The violations listed here began between January 2017 and October 2024. By type: 9 monitoring and reporting, 2 required treatment not met and 1 reporting. The contaminant or rule involved most often is E. coli (2 of them). EPA lists 12 as resolved. Resolved means at least one resolving action is on record: the system returned to compliance, the rule no longer applies, or no further action was needed.
| Began | Violation | Contaminant or rule | Health-based | Status |
|---|---|---|---|---|
| 2024-10-17 | ReportingLSL Reporting · code 4G | Lead and Copper Rule Revisionscode 5200 | No | Resolved |
| 2021-12-01 | Required treatment not metSingle Turbidity Exceed (Enhanced SWTR) · code 43 | Interim Enhanced Surface Water Treatment Rulecode 0300 | Yes | Resolved |
| 2021-12-01 | Required treatment not metTreatment Technique (SWTR and GWR) · code 41 | Surface Water Treatment Rulecode 0200 | Yes | Resolved |
| 2018-04-01 | Monitoring and reportingMonitoring, Source Water (LT2) · code 32 | E. colicode 3014 | No | Resolved |
| 2017-07-01 | Monitoring and reportingMonitoring, Source Water (LT2) · code 32 | E. colicode 3014 | No | Resolved |
| 2017-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Benzenecode 2990 | No | Resolved |
| 2017-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,1,1-Trichloroethanecode 2981 | No | Resolved |
| 2017-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Chlorobenzenecode 2989 | No | Resolved |
| 2017-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,1-Dichloroethylenecode 2977 | No | Resolved |
| 2017-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | p-Dichlorobenzenecode 2969 | No | Resolved |
| 2017-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | 1,1,2-Trichloroethanecode 2985 | No | Resolved |
| 2017-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Xylenes, Totalcode 2955 | No | Resolved |
The 12 most recent violations in EPA's records, newest first.Labels and codes come from EPA's SDWIS reference tables. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found. "Health-based" marks violations of a legal limit or required treatment.
City of Louisville: frequently asked questions
Who runs City of Louisville?
City of Louisville (PWSID CO0107487) is a community water system owned by a local government. It is regulated by the CO state drinking water program.
How many people does City of Louisville serve?
City of Louisville reports serving 20,975 people through 7,368 service connections in Boulder County, Colorado.
Where does City of Louisville get its water?
EPA SDWIS lists this system's primary water source as surface water. Surface water means the system draws its water from rivers, lakes, streams or reservoirs.
Does City of Louisville have any drinking water violations?
Of the 12 most recent violations in EPA's records, 2 are health-based, and the most recent began in October 2024. A monitoring or reporting violation means a required test or report was missed or late; it does not by itself mean a contaminant was found.
Is City of Louisville's water safe to drink?
AquaCensus shows EPA compliance records, not current water test results, so it cannot say whether the water is safe at a given moment. Of the 12 most recent violations in EPA's records, 2 are health-based, and the most recent began in October 2024. For current results, consult the system's annual water quality report, EPA ECHO, or the CO state drinking water program.
Where can I find City of Louisville's water quality report?
As a community water system, City of Louisville must deliver an annual water quality report, called a Consumer Confidence Report, to its customers by July 1 each year, covering the previous calendar year. The system can provide a copy on request.
Other water systems in Boulder County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Boulder City of | Boulder | 166,080 | Community | Surface water |
| Longmont City of | Boulder | 104,178 | Community | Surface water |
| Erie Town of | Boulder | 47,444 | Community | Surface water |
| Lafayette City of | Boulder | 28,700 | Community | Surface water |
| Left Hand Wd | Boulder | 20,280 | Community | Surface water |
| Superior Md No 1 | Boulder | 17,900 | Community | Surface water |
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About this data
Source: U.S. EPA Safe Drinking Water Information System (SDWIS) and SDWA violation records, via EPA ECHO, as published October 1, 2026 — AquaCensus refreshes it quarterly. See the methodology for how records are matched, cleaned and scored.
Cite as: AquaCensus, “Louisville City of, PWSID CO0107487, Colorado”, https://aquacensus.com/water-systems/colorado/louisville-city-of-co0107487 (data as of October 1, 2026).