Monroe South County, MI
Lead detected, under the action levels
Latest 90th-percentile lead: 1 ppb (monitoring period 2025-2025). The federal action level is 15 ppb today and drops to 10 ppb in Nov 2027; EPA's health goal is 0. Lead was measured in sampled homes but the 90th percentile is under both action levels. EPA's health goal for lead is zero, so test your own tap if your home was built before 1986 or anyone in it is pregnant or a young child.
About Monroe South County
Monroe South County serves about 33,816 people through 11,272 service connections, which makes it a large system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws surface water, in Monroe County, Michigan. EPA system ID: MI0004455; phone on file: 734-240-3109. Ask them for your address in their service line inventory - every system had to publish one by Oct 2024.
Every lead result on file
Against the period ending 2024 (1 ppb) the latest result is about the same. The highest 90th-percentile result EPA holds for Monroe South County is 1 ppb across 8 monitoring periods, none of them over 15 ppb.
| Period ending | 90th-percentile lead |
|---|---|
| 2025 | 1 ppb |
| 2024 | 1 ppb |
| 2023 | 0 (not detected) |
| 2022 | 0 (not detected) |
| 2021 | 1 ppb |
| 2020 | 0 (not detected) |
| 2019 | 0 (not detected) |
| 2017 | 1 ppb |
Against other Michigan systems
Of the 1,227 Michigan systems with a lead result, the median latest reading is 1 ppb; 31 are over 15 ppb right now and 109 have gone over at some point. Monroe South County's 1 ppb sits at the 50th percentile in Michigan and the 56th nationally (higher means more lead).
Nearby utilities
9 other systems share Monroe County; 3 of them have a higher latest lead result than Monroe South County. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Monroe | 49,467 | 2 ppb |
| Frenchtown Township | 21,609 | 1.9 ppb |
| Berlin Township | 9,900 | 0 (not detected) |
| Ash Township | 5,959 | 7.6 ppb |
| Dundee | 5,400 | 0 (not detected) |
| South Rockwood | 1,587 | 0 (not detected) |
| Petersburg | 1,115 | 0 (not detected) |
| Whiteford Township | 303 | 0 (not detected) |
| Gilbert Mobile Home Park | 150 | - |
What to do in your house
Test your own tap with a certified lab first-draw sample; Monroe, MI may offer free or low-cost kits through the utility. If your own line is lead, replacing the private side runs about $1,200-$12,300 (EPA average about $4,700). Ask Monroe South County whether it covers that cost before hiring anyone - many utilities now do.
These figures describe homes the utility sampled, not your tap. Only your service line record or a test of your own water answers the question for your house. The lead result guide covers how utilities pick the homes they sample. Size matters more than most people expect: small vs large water systems.