Public water system · WI1220117
ActivePotosi Waterworks
At a glance
Potosi Waterworks (PWSID WI1220117) is an active community water system in Grant County, Wisconsin. It reports serving 718 people through 265 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in March 2024.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
718
Service connections
265
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Potosi Waterworks compare with other water systems in Grant County?
By EPA's size categories, Potosi Waterworks is a small system (501 to 3,300 people). Grant County has 90 active public water systems. Its population served is about 55% above the county average of 463 people per system, and accounts for 1.7% of the 41,674 people reported by systems filed under the county. Across Wisconsin, the 11,056 active systems average 469 people each. Nationally, the average active community water system reports serving 6,703 people, so Potosi Waterworks is well below 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. Wisconsin has 1,053 active community water systems, 9.5% of the state's 11,056 active systems. Groundwater means the system draws its water from wells or springs fed by underground aquifers. 10,978 Wisconsin systems (99%) list groundwater as their primary source.
Who owns and regulates Potosi Waterworks?
EPA lists Potosi Waterworks as owned by a local government. The WI state drinking water program is its primacy agency, the regulator with primary enforcement responsibility for the system under the Safe Drinking Water Act. 21 of the 90 active systems in Grant County (23%) are also owned by a local government.
Does Potosi Waterworks have drinking water violations?
Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in March 2024. The violations listed here began between May 1996 and March 2024. By type: 7 monitoring and reporting, 2 required treatment not met, 1 monitoring, 1 public notice, recordkeeping or other and 1 contaminant level above the legal limit. The contaminant or rule involved most often is Lead and Copper Rule (3 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 |
|---|---|---|---|---|
| 2024-03-01 | Required treatment not metTreatment Technique No Certif. Operator · code 12 | Stage 1 Disinfectants and Disinfection Byproducts Rulecode 0400 | Yes | Resolved |
| 2024-01-01 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2018-05-02 | Required treatment not metTreatment Technique No Certif. Operator · code 12 | Stage 1 Disinfectants and Disinfection Byproducts Rulecode 0400 | Yes | Resolved |
| 2018-03-01 | MonitoringMonitoring, Routine (RTCR) · code 3A | Revised Total Coliform Rulecode 8000 | No | Resolved |
| 2018-01-01 | Monitoring and reportingMonitoring, Regular · code 03 | Gross alpha (excluding radon and uranium)code 4000 | No | Resolved |
| 2015-01-01 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 2013-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2013-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Total trihalomethanes (TTHM)code 2950 | No | Resolved |
| 2013-01-01 | Monitoring and reportingMonitoring and Reporting (DBP) · code 27 | Haloacetic acids (HAA5)code 2456 | No | Resolved |
| 2012-01-01 | Monitoring and reportingLead Consumer Notice · code 66 | Lead and Copper Rulecode 5000 | No | Resolved |
| 1997-11-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
| 1996-05-01 | Contaminant level above the legal limitMaximum Contaminant Level Violation, Monthly (TCR) · code 22 | Total coliform bacteria (TCR)code 3100 | Yes | 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.
Potosi Waterworks: frequently asked questions
Who runs Potosi Waterworks?
Potosi Waterworks (PWSID WI1220117) is a community water system owned by a local government. It is regulated by the WI state drinking water program.
How many people does Potosi Waterworks serve?
Potosi Waterworks reports serving 718 people through 265 service connections in Grant County, Wisconsin.
Where does Potosi Waterworks get its water?
EPA SDWIS lists this system's primary water source as groundwater. Groundwater means the system draws its water from wells or springs fed by underground aquifers.
Does Potosi Waterworks have any drinking water violations?
Of the 12 most recent violations in EPA's records, 3 are health-based, and the most recent began in March 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 Potosi Waterworks' 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, 3 are health-based, and the most recent began in March 2024. For current results, consult the system's annual water quality report, EPA ECHO, or the WI state drinking water program.
Where can I find Potosi Waterworks' water quality report?
As a community water system, Potosi Waterworks 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 Grant County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Platteville Waterworks | Grant | 12,268 | Community | Groundwater |
| Lancaster Waterworks | Grant | 3,907 | Community | Groundwater |
| Boscobel Waterworks | Grant | 3,237 | Community | Groundwater |
| Fennimore Waterworks | Grant | 2,507 | Community | Groundwater |
| Cuba City Waterworks | Grant | 2,141 | Community | Groundwater |
| Muscoda Waterworks | Grant | 1,453 | Community | Groundwater |
Related pages
Working with water-system records? Pro adds alerts, change history and CSV export ($49/mo); Enterprise adds full national files, the API and an MCP server for AI tools.
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, “Potosi Waterworks, PWSID WI1220117, Wisconsin”, https://aquacensus.com/water-systems/wisconsin/potosi-waterworks-wi1220117 (data as of October 1, 2026).