Tuscola County, Michigan: drinking water report. Tuscola County in Michigan's Thumb region has about 52,000 residents in small communities including Caro
Tuscola County in Michigan's Thumb region has about 52,000 residents in small communities including Caro and Vassar. The county is deeply agricultural – sugar beets, dry beans, corn, and dairy dominate the landscape. Nearly all drinking water comes from groundwater, with most residents on private wells. The flat, tile-drained farmland creates a direct pathway from fields to aquifer.
Nitrate contamination is pervasive in Tuscola County's shallow aquifer. According to Michigan EGLE's 2024 private well testing data, 20% of tested wells in the county exceeded the nitrate MCL of 10 mg/L. The combination of sandy soils, heavy fertilizer application on sugar beet and corn fields, and tile drainage moves nitrogen through the system with little natural attenuation.
A 2024 Michigan State University Extension study found that wells in the vicinity of concentrated animal feeding operations showed the highest nitrate concentrations, with some exceeding 30 mg/L – three times the MCL. PFAS from the former Caro airport has been detected at 5 ppt in monitoring wells, below federal MCLs.
Tuscola County's agricultural intensity and sandy soils make nitrate contamination a near-certainty for many private wells. One in five wells exceeds the safe limit, and the actual rate may be higher since not all wells are tested regularly.
We recommend checking your water for any available data and testing your well if results are not on file. For nitrate at the concentrations found in this area, reverse osmosis is the most reliable household treatment. Our water filter guide covers systems certified for agricultural contaminants. Pull your detailed report for context, and visit our Michigan page for statewide data.