Public water system · WI2681104

Active

Knollcrest

At a glance

Knollcrest (PWSID WI2681104) is an active community water system in Waukesha County, Wisconsin. It reports serving 66 people through 52 service connections. Its primary water source is groundwater, and EPA lists it as privately owned. Of the 12 most recent violations in EPA's records, 5 are health-based, and the most recent began in August 2021.

Dataset updated October 2026 . Source: EPA SDWIS/ECHO public records.

Population served

Service connections

Primary source

Groundwater

System type

CWS

Community water system

System record

PWSIDWI2681104

System typeCommunity water system

Activity statusActive

Population served66

Service connections52

Primary water sourceGroundwater

Owner typePrivate

Primacy agencyWI state drinking water program

City servedDelafield

StateWisconsin

ZIP—

CountyWaukesha County

How does Knollcrest compare with other water systems in Waukesha County?

By EPA's size categories, Knollcrest is a very small system (500 people or fewer). Waukesha County has 589 active public water systems. Its population served is well below the county average of 549 people per system, and accounts for less than 0.1% of the 323,265 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 Knollcrest 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 Knollcrest?

EPA lists Knollcrest as privately owned. 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. 452 of the 589 active systems in Waukesha County (77%) are also privately owned.

Does Knollcrest have drinking water violations?

Of the 12 most recent violations in EPA's records, 5 are health-based, and the most recent began in August 2021. The violations listed here began between January 2000 and August 2021. By type: 6 monitoring and reporting, 5 contaminant level above the legal limit and 1 public notice, recordkeeping or other. The contaminant or rule involved most often is Di(2-ethylhexyl) phthalate (5 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
2021-08-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02	Di(2-ethylhexyl) phthalatecode 2039	Yes	Resolved
2021-01-01	Monitoring and reportingLead Consumer Notice · code 66	Lead and Copper Rulecode 5000	No	Resolved
2011-01-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02	Di(2-ethylhexyl) phthalatecode 2039	Yes	Resolved
2010-10-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02	Di(2-ethylhexyl) phthalatecode 2039	Yes	Resolved
2010-07-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02	Di(2-ethylhexyl) phthalatecode 2039	Yes	Resolved
2010-04-01	Contaminant level above the legal limitMaximum Contaminant Level Violation, Average · code 02	Di(2-ethylhexyl) phthalatecode 2039	Yes	Resolved
2005-01-01	Monitoring and reportingFollow-up Or Routine LCR Tap M/R · code 52	Lead and Copper Rulecode 5000	No	Resolved
2005-01-01	Public notice, recordkeeping or otherPublic Notification Violation for NPDWR Violation · code 75	Public Noticecode 7500	No	Resolved
2003-09-01	Monitoring and reportingMonitoring, Routine Major (TCR) · code 23	Total coliform bacteria (TCR)code 3100	No	Resolved
2001-06-01	Monitoring and reportingMonitoring, Routine Major (TCR) · code 23	Total coliform bacteria (TCR)code 3100	No	Resolved
2000-01-01	Monitoring and reportingMonitoring, Regular · code 03	Tetrachloroethylenecode 2987	No	Resolved
2000-01-01	Monitoring and reportingMonitoring, Regular · code 03	trans-1,2-Dichloroethylenecode 2979	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.

Knollcrest: frequently asked questions

Who runs Knollcrest?

Knollcrest (PWSID WI2681104) is a community water system privately owned. It is regulated by the WI state drinking water program.

How many people does Knollcrest serve?

Knollcrest reports serving 66 people through 52 service connections in Waukesha County, Wisconsin.

Where does Knollcrest 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 Knollcrest have any drinking water violations?

Of the 12 most recent violations in EPA's records, 5 are health-based, and the most recent began in August 2021. 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 Knollcrest'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, 5 are health-based, and the most recent began in August 2021. For current results, consult the system's annual water quality report, EPA ECHO, or the WI state drinking water program.

Where can I find Knollcrest's water quality report?

As a community water system, Knollcrest 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 Waukesha County

Water system	County	Population served	Type	Source
Waukesha Water Utility	Waukesha	70,718	Community	Purchased surface water
Brookfield Water Utility	Waukesha	29,070	Community	Groundwater
New Berlin Water Utility	Waukesha	27,899	Community	Purchased surface water
Menomonee Falls Ww - Surface Water	Waukesha	23,867	Community	Purchased surface water
Oconomowoc Waterworks	Waukesha	15,805	Community	Groundwater
Sussex Village Hall & Water Utility	Waukesha	11,750	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, “Knollcrest, PWSID WI2681104, Wisconsin”, https://aquacensus.com/water-systems/wisconsin/knollcrest-wi2681104 (data as of October 1, 2026).