Public water system · WI4150510
ActiveSister Bay Waterworks
At a glance
Sister Bay Waterworks (PWSID WI4150510) is an active community water system in Door County, Wisconsin. It reports serving 1,000 people through 1,507 service connections. Its primary water source is groundwater, and EPA lists it as owned by a local government. EPA's records list 3 violations for this system; none is health-based, and the most recent began in July 2015.
Dataset updated . Source: EPA SDWIS/ECHO public records.
Population served
1,000
Service connections
1,507
Primary source
GW
Groundwater
System type
CWS
Community water system
System record
How does Sister Bay Waterworks compare with other water systems in Door County?
By EPA's size categories, Sister Bay Waterworks is a small system (501 to 3,300 people). Door County has 451 active public water systems, and Sister Bay Waterworks is the 3rd-largest of them by population served. Its population served is about 13 times the county average of 77 people per system, and accounts for 2.9% of the 34,679 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 Sister Bay 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 Sister Bay Waterworks?
EPA lists Sister Bay 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. 45 of the 451 active systems in Door County (10%) are also owned by a local government.
Does Sister Bay Waterworks have drinking water violations?
EPA's records list 3 violations for this system; none is health-based, and the most recent began in July 2015. The violations listed here began between May 1995 and July 2015. By type: 2 public notice, recordkeeping or other and 1 monitoring and reporting. The contaminant or rule involved most often is Consumer Confidence Rule (2 of them). EPA lists 3 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 |
|---|---|---|---|---|
| 2015-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 2001-07-01 | Public notice, recordkeeping or otherConsumer Confidence Report Complete Failure to Report · code 71 | Consumer Confidence Rulecode 7000 | No | Resolved |
| 1995-05-01 | Monitoring and reportingMonitoring, Routine Minor (TCR) · code 24 | Total coliform bacteria (TCR)code 3100 | No | Resolved |
All 3 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.
Sister Bay Waterworks: frequently asked questions
Who runs Sister Bay Waterworks?
Sister Bay Waterworks (PWSID WI4150510) is a community water system owned by a local government. It is regulated by the WI state drinking water program.
How many people does Sister Bay Waterworks serve?
Sister Bay Waterworks reports serving 1,000 people through 1,507 service connections in Door County, Wisconsin.
Where does Sister Bay 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 Sister Bay Waterworks have any drinking water violations?
EPA's records list 3 violations for this system; none is health-based, and the most recent began in July 2015. 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 Sister Bay 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. EPA's records list 3 violations for this system; none is health-based, and the most recent began in July 2015. For current results, consult the system's annual water quality report, EPA ECHO, or the WI state drinking water program.
Where can I find Sister Bay Waterworks' water quality report?
As a community water system, Sister Bay 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 Door County
| Water system | County | Population served | Type | Source |
|---|---|---|---|---|
| Sturgeon Bay Waterworks | Door | 9,700 | Community | Groundwater |
| Southern Door Sch Dist | Door | 1,350 | Non-transient non-community | Groundwater |
| Sevastopol High Sch | Door | 715 | Non-transient non-community | Groundwater |
| Gibraltar High School | Door | 695 | Non-transient non-community | Groundwater |
| Loft | Door | 308 | Transient non-community | Groundwater |
| Culvers Town & Country C Store | Door | 265 | Transient non-community | Groundwater |
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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, “Sister Bay Waterworks, PWSID WI4150510, Wisconsin”, https://aquacensus.com/water-systems/wisconsin/sister-bay-waterworks-wi4150510 (data as of October 1, 2026).