01The verdict: is Corunna water safe?
Corunna's tap water meets most EPA standards but has areas that warrant attention. With a grade of A (90.2/100), some contaminant levels or compliance issues suggest that residents may benefit from additional filtration. The city's 1 water system serves approximately 2,028 residents using groundwater (wells).
Chlorate is over its legal limit
Measured at 270.0 µg/L against the EPA Lifetime HA of 210 µg/L. The ledger below shows how far over — and which filter removes it.
See the measurement ↓Lead is well under the limit
90th-percentile lead is 0.0 ppb — beneath the 15 ppb federal action level and under the 5 ppb watch threshold.
See the trend ↓A flood-prone service area
5 federal disaster declarations on record. After severe weather, watch for boil-water advisories.
See the risk factors ↓Corunna's drinking water received a grade of A (90.2 out of 100), indicating excellent water quality. The city's 1 water system serves approximately 2,028 residents using purchased ground water.
Lead levels were measured at 0.0 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 2 violations on record, including 0 health-based violations. 1 remains unresolved.
Corunna ranks #110 out of 513 cities in Michigan for water quality, placing it above average in the state. Corunna purchases its water from a regional wholesaler, meaning quality depends on both the supplier's treatment and the local distribution system's condition. Hexavalent chromium (chromium-6) was detected at 0.35 µg/L in UCMR 3 testing. While below California's 10 µg/L limit and with no federal MCL set, residents sensitive to this contaminant may consider reverse osmosis filtration. As a small community water system, Corunna may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
02What's in Corunna's water
Every contaminant flagged in Corunna, 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. | 0.0 | 15 | ppb | Inorganic | Safe |
Cities ranked by 90th-percentile lead PF PFAS in Michigan
Cities ranked by compounds detected Cu Copper in Michigan
Cities ranked by 90th-percentile copper
03Corunna'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 2 violations on record, including 0 health-based violations. 1 remains 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 0 ppb since 1993. Latest reading: 0 ppb (2024) — 0% of the action level. Sampled at higher-risk homes (90th percentile).
04Where Corunna's water comes from
Corunna purchases its water supply from a regional wholesale provider rather than treating raw water directly.
Purchased Groundwater
Water is bought from a regional wholesaler; quality starts at the supplier's intake and treatment.
Wholesale supplier
Primary treatment happens at the wholesaler; the local utility maintains disinfectant residual in its pipes.
1 system
1 water system, operated under local government ownership.
2,028 people
Residents served across Corunna's service area.
Water quality depends on both the wholesaler's treatment standards and the condition of Corunna's local distribution pipes and storage facilities. Purchased water systems are common in suburban areas and smaller communities that lack the infrastructure for independent treatment. The system is operated by local government ownership and serves approximately 2,028 people through 1 water system.
| System name | PWSID | Population | Source |
|---|---|---|---|
| CORUNNA, CITY OF | MI0001640 | 2,028 | Purchased Groundwater |
Water bodies near Corunna
These water bodies shape the regional watershed and can indirectly affect groundwater quality.
05Pressure on Corunna'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
5 facilities within 10 miles reported 250 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
5 federal disaster declarations on record for Shiawassee County. Flooding and severe storms can overwhelm treatment plants, cause sewage overflows, and push runoff into supplies.
06How Corunna compares
Scores for nearby Michigan cities on one line, with the average marked.
dashed line = Michigan average (70/100)
Corunna scores 90.2/100 — above the Michigan average of 70/100. It outscores 8 of 10 nearby cities. Full Michigan rankings →
84.1 / 100BGrand Rapids, MI
70.2 / 100DAnn Arbor, MI
51.5 / 100CLansing, MI
57.3 / 100FKalamazoo, MI
35 / 100DFlint, MI
45.8 / 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 Corunna's water — not generic advice.
A basic carbon filter still helps
Corunna'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 Corunna 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 Corunna, MI tap water safe to drink?
Corunna's water quality earned a grade of A (90.2/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #110 out of 513 cities tested in Michigan.
What contaminants are in Corunna's water?
Lead was measured at 0.0 ppb (90th percentile). 2 violations are on record.
How is Corunna'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 Corunna?
Based on current data, basic filtration should suffice for additional peace of mind.
Where does Corunna's water come from?
Corunna's water is sourced from Purchased ground water. The city has 1 water system serving approximately 2,028 residents.
Is Corunna's groundwater at risk of contamination?
Corunna 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 2 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 Corunna's water compare to other cities?
Corunna ranks #110 out of 513 cities in Michigan (better than 79% of state cities) and #2348 out of 15382 cities nationally (85th percentile). The grade of A reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Corunna's small water system affect quality?
Corunna's system serves approximately 2,028 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 2 violations on record.