Is Delafield, WI Tap Water Safe to Drink?
Graded D, with 85 unresolved violations on record. See what was cited — and what it means for your tap. What to do next ↓
47/100
waterverge.com Delafield, WI — Water Quality Report
Delafield's drinking water received a grade of D (47 out of 100), indicating poor water quality. The city's 17 water systems serve approximately 2,368 residents using groundwater.
Lead levels were measured at 1.2 ppb (90th percentile), well within EPA limits. This system has not yet been tested for PFAS under the EPA UCMR 5 program.
The system has 281 violations on record, including 22 health-based violations. 85 remain unresolved.
What to know about Delafield's water
Delafield ranks #422 out of 446 cities in Wisconsin for water quality, placing it among the lowest-rated in the state.
Delafield relies on groundwater, which is generally less vulnerable to surface contamination but can be affected by naturally occurring minerals like arsenic and nitrate, as well as agricultural and industrial runoff.
As a small community water system, Delafield may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
The system has seen 44 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Delafield, WI water safe to drink?
Delafield's drinking water has significant quality concerns based on EPA testing data. With a grade of D (47/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 17 water systems serve approximately 2,368 residents using groundwater (wells).
Recent water quality updates for Delafield
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Delafield's water quality assessment. Grade: D (47/100).
Federal disaster declaration (FEMA DR-4892). Flood event — may have impacted local water infrastructure.
Contaminants: Revised Total Coliform Rule.
Contaminants: Lead and Copper Rule.
4 health-based. Contaminants: LEAD AND COPPER RULE REVISIONS, Public Notice.
Federal disaster declaration (FEMA DR-3249). Hurricane event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Delafield's water supply.
Well within EPA limits.
Violation history
Delafield's water system has 281 total violations on record, including 22 health-based violations. 85 remain unresolved. 44 violations were issued in the last 5 years.
Flood & environmental risk
Waukesha County has experienced 7 federally declared disasters since 1969. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies. Local water sources include Menomonee River, Fox River.
Where does Delafield's water come from?
Delafield's drinking water comes from groundwater (wells), supplied by 17 water systems serving approximately 2,368 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include Menomonee River (river), Fox River (river).
What Delafield residents can do
Recommended: NSF-certified water filter. This addresses the specific contaminants found in Delafield's water.
Your water utility is required to publish an annual Consumer Confidence Report (CCR) with detailed testing results. Ask for the latest copy or check your utility's website.
Delafield's area has a history of flooding. After severe weather, watch for boil water advisories from your local utility.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violation summary
Violations & advisories
Top industrial polluters within 10 miles of Delafield
Industrial polluters nearby
Reported releases to surface water by facilities near Delafield, ranked by pounds discharged annually.
Total reported releases to surface water: 89 lbs
| Facility | Top chemical | To surface water (lbs/yr) | Distance |
|---|---|---|---|
METALTEK INTERNATIONAL-WISCO NSIN CENTRIFUGAL DIV WAUKESHA, WI53188 | Copper | 64 | 8.9 mi |
NORTHERN STAINLESS CORP PEWAUKEE, WI53072 | Copper | 15 | 7.1 mi |
WAUKESHA FOUNDRY INC WAUKESHA, WI53186 | Copper compounds | 9 | 9.9 mi |
CASTALLOY INC. WAUKESHA, WI53189 | Manganese | 1 | 9.4 mi |
ESSENTIAL INDUSTRIES INC MERTON, WI53056 | — | — | 7.0 mi |
Source: EPA Toxic Release Inventory (TRI) 2023
Flood & disaster history
Waukesha County has experienced 7 federally declared disasters since 1969. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 1.2 | 15 | ppb | Inorganic | Safe |
Lead level trend (90th percentile)
See how Delafield compares by contaminant
Explore where Delafield ranks among all Wisconsin cities for specific contaminants.
Water source & infrastructure
Where Delafield's water comes from
Delafield's drinking water is drawn from underground aquifers through wells.
Groundwater is naturally filtered through rock and soil layers, generally requiring less treatment than surface water. However, it can contain naturally occurring contaminants like arsenic, radon, and minerals.
Agricultural activity, septic systems, and industrial operations near well fields can introduce nitrates, pesticides, and volatile organic compounds.
The system is operated by private ownership and serves approximately 2,368 people through 17 water systems.
Water bodies near Delafield
Delafield is located near 2 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Delafield
| System Name | PWSID | Population | Source |
|---|---|---|---|
| DELAFIELD SQUARE | WI2685812 | 587 | GW |
| NASHOTAH HOUSE | WI2682512 | 350 | GW |
| ST JOHNS NORTHWESTERN ACADEMIES | WI2680761 | 340 | GW |
| DELAFIELD WATERWORKS | WI2684642 | 300 | GW |
| ARBORS | WI2682795 | 280 | GW |
| LAKE COUNTRY APARTMENTS | WI2682229 | 84 | GW |
| APARTMENTS OF STONERIDGE | WI2682761 | 75 | GW |
| KNOLLCREST | WI2681104 | 66 | GW |
| DELAFIELD LAKES 402 | WI2686101 | 50 | GW |
| CAMBRIDGE PLACE OF DELAFIELD | WI2686325 | 50 | GW |
| QUAIL HOLLOW CONDOS | WI2686359 | 30 | GW |
| DELAFIELD WOODS 411 | WI2686336 | 28 | GW |
| SANCTUARY OF DELAFIELD | WI2685951 | 27 | GW |
| DELAFIELD WOODS 828 | WI2686337 | 26 | GW |
| DELAFIELD LAKES 404 | WI2686114 | 25 | GW |
| WELLS ST STATION 425 WEST | WI2686466 | 25 | GW |
| WELLS ST STATION 435 EAST | WI2686619 | 25 | GWP |
How Delafield compares
Full Wisconsin rankings →Delafield's score of 47/100 is below the average of 65/100 among major Wisconsin cities. It outscores 2 of 10 nearby cities. 8 of 10 nearby cities score higher.
Nearby cities
View Wisconsin rankings →About Delafield, WI
Wikipedia →Pewaukee is a city in Waukesha County, Wisconsin, United States. The population was 15,914 at the 2020 census. It is part of the Milwaukee metropolitan area. Pewaukee, originally organized as a town in 1840 and later as a city in 1999, surrounds the Village of Pewaukee, which was incorporated from the town in 1876.
Learn more about your water
Guides and resources related to Delafield's water quality findings.
Explore water quality across Waukesha
Frequently asked questions
Is Delafield, WI tap water safe to drink?
Delafield's water quality earned a grade of D (47/100). Significant issues have been found. A water filter is strongly recommended. The city ranks #422 out of 446 cities tested in Wisconsin.
What contaminants are in Delafield's water?
Lead was measured at 1.2 ppb (90th percentile). 281 violations are on record.
How is Delafield's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in Delafield?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Delafield's water come from?
Delafield's water is sourced from Groundwater. The city has 17 water systems serving approximately 2,368 residents.
What health violations has Delafield's water system had?
Delafield has 22 health-based violations on record. The most recent violation was recorded in April 2025. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 85 violations remain unresolved.
Is Delafield's groundwater at risk of contamination?
Delafield uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. The system has 281 violations on record that may relate to groundwater quality. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS.
How does Delafield's water compare to other cities?
Delafield ranks #422 out of 446 cities in Wisconsin (better than 5% of state cities) and #13739 out of 15744 cities nationally (13th percentile). The grade of D reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.