01The verdict: is Black Earth water safe?
Black Earth's drinking water has significant quality concerns based on EPA testing data. With a grade of A- (85.3/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 1 water system serves approximately 1,493 residents using groundwater (wells).
4 unresolved violations on record
EPA records show open compliance items for this system. Most are administrative, but unresolved items are worth watching.
See what was cited ↓Lead is well under the limit
90th-percentile lead is 2.4 ppb — beneath the 15 ppb federal action level and under the 5 ppb watch threshold.
See the trend ↓2 violations in the last five years
Recent compliance history is the best predictor of future problems — the year-by-year record is below.
See the record ↓Black Earth's drinking water received a grade of A- (85.3 out of 100), indicating good water quality. The city's 1 water system serves approximately 1,493 residents using groundwater.
Lead levels were measured at 2.4 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 12 violations on record, including 4 health-based violations. 4 remain unresolved.
Black Earth ranks #165 out of 441 cities in Wisconsin for water quality, placing it mid-range in the state. Black Earth 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, Black Earth may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
02What's in Black Earth's water
Every contaminant flagged in Black Earth, on one shared scale: distance to its own legal limit. The red line is the limit — anything past it is out of compliance, and the closer a bar gets, the less headroom the system has.
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. | 2.4 | 15 | ppb | Inorganic | Safe |
Cities ranked by 90th-percentile lead PF PFAS in Wisconsin
Cities ranked by compounds detected Cu Copper in Wisconsin
Cities ranked by 90th-percentile copper
03Black Earth's ten-year track record
Each box is one year. A green check means no EPA violations; a numbered badge counts that year's violations — red if any were health-based, amber if they were monitoring or paperwork issues. The system has 12 violations on record, including 4 health-based violations. 4 remain unresolved.
9 of the last ten years were clean. The numbered years had EPA violations — red when any were health-based, amber when they were paperwork or missed-testing issues.
▼ Down 1.1 ppb since 1993. Latest reading: 2.4 ppb (2023) — 16% of the action level. Sampled at higher-risk homes (90th percentile).
04Where Black Earth's water comes from
Black Earth's drinking water is drawn from underground aquifers through wells.
Groundwater
Underground aquifers reached by wells — naturally filtered, but can carry minerals like arsenic and nitrate.
Local treatment
Groundwater generally needs less treatment — typically disinfection and, where needed, mineral removal.
1 system
1 water system, operated under local government ownership.
1,493 people
Residents served across Black Earth's service area.
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 local government ownership and serves approximately 1,493 people through 1 water system.
| System name | PWSID | Population | Source |
|---|---|---|---|
| BLACK EARTH WATERWORKS | WI1130211 | 1,493 | Groundwater |
Water bodies near Black Earth
These water bodies shape the regional watershed and can indirectly affect groundwater quality.
05Pressure on Black Earth's watershed
Outside forces that shape what reaches the treatment plant. None of these is a verdict on the tap by itself — but each adds pressure worth knowing about.
Industrial discharge
1 facility within 10 miles reported 0 lb released to surface water in the latest EPA Toxics Release Inventory. Proximity doesn't equal tap contamination — treatment and hydrology decide — but it's pressure on the watershed.
Flood & storm history
3 federal disaster declarations on record for Dane County. Flooding and severe storms can overwhelm treatment plants, cause sewage overflows, and push runoff into supplies.
Superfund proximity
1 National Priorities List site within 10 miles. Proximity does not necessarily indicate tap-water contamination — the connection depends on hydrology and treatment.
Drought
Dane County is in D1 (moderate drought) per the U.S. Drought Monitor (week of Jul 2026). Drought can raise disinfection-byproduct levels and taste/odor issues as utilities draw from lower reservoirs.
06How Black Earth compares
Scores for nearby Wisconsin cities on one line, with the average marked.
dashed line = Wisconsin average (65/100)
Black Earth scores 85.3/100 — above the Wisconsin average of 65/100. It outscores 7 of 10 nearby cities. Full Wisconsin rankings →
90.2 / 100FMadison, WI
35.4 / 100DGreen Bay, WI
54 / 100CRacine, WI
69.5 / 100DKenosha, WI
45.8 / 100DWaukesha, WI
47.1 / 100
Compare all cities in the county — grades, violations, and contaminant data side by side.→
07What to do at home
Steps matched to what testing actually found in Black Earth's water — not generic advice.
A basic carbon filter still helps
Black Earth's water meets federal standards, but a simple carbon filter improves taste and adds a margin of safety against short-term issues.
Compare tested filters →Read your utility's annual report
Every utility must publish a yearly Consumer Confidence Report with its own testing results. It pairs well with the independent data on this page.
How to read a CCR →Watch for Black Earth alerts
This area has a history of flood declarations — after severe weather, watch for boil-water advisories from the utility, and check the live alerts on this page.
All water alerts →Frequently asked questions
Is Black Earth, WI tap water safe to drink?
Black Earth's water quality earned a grade of A- (85.3/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #165 out of 441 cities tested in Wisconsin.
What contaminants are in Black Earth's water?
Lead was measured at 2.4 ppb (90th percentile). 12 violations are on record.
How is Black Earth'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 Black Earth?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Black Earth's water come from?
Black Earth's water is sourced from Groundwater. The city has 1 water system serving approximately 1,493 residents.
What health violations has Black Earth's water system had?
Black Earth has 4 health-based violations on record. The most recent violation was recorded in October 2024. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 4 violations remain unresolved.
Is Black Earth's groundwater at risk of contamination?
Black Earth 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 12 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 Black Earth's water compare to other cities?
Black Earth ranks #165 out of 441 cities in Wisconsin (better than 63% of state cities) and #5361 out of 15382 cities nationally (65th percentile). The grade of A- reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Black Earth's small water system affect quality?
Black Earth's system serves approximately 1,493 residents. Small community water systems (under 3,300 people) may have fewer financial resources for infrastructure upgrades and advanced treatment technologies. However, they are held to the same EPA drinking water standards as larger systems. This system has 12 violations on record.