Macoupin County, Illinois: drinking water report. Macoupin County sits in the central Illinois prairie, home to communities including Carlinville, Virden,…
Macoupin County sits in the central Illinois prairie, home to communities including Carlinville, Virden, Gillespie, and Staunton. Most residents rely on groundwater from private wells or small municipal systems drawing from the Pennsylvanian aquifer and glacial drift deposits. Unlike counties with major surface water sources, Macoupin's water infrastructure consists primarily of dozens of small-scale operations serving populations under 10,000.
Central Illinois counties face distinct water quality challenges tied to both agricultural legacy and aging infrastructure. Macoupin County sits in a region where nitrate contamination from decades of corn and soybean production affects shallow groundwater supplies. Private wells, which serve a substantial portion of the rural population here, typically lack the treatment capacity of municipal systems and may show elevated nitrate levels, particularly in areas with intensive farming history or near livestock operations.
The county's small water systems face compliance challenges common to rural Illinois. Lead service lines remain present in older sections of communities like Carlinville and Virden, where housing stock dates to the early 1900s. Illinois enacted stricter lead testing requirements in recent years, but many small utilities struggle with sampling protocols and remediation costs. Residents in homes built before 1986 face higher exposure risk, especially in the first-draw morning water that sits in pipes overnight.
PFAS contamination is an emerging concern across Illinois, though comprehensive testing in rural counties remains incomplete. The EPA's UCMR5 monitoring program required testing at larger systems, but many of Macoupin County's smaller utilities fell below the testing threshold. Regional patterns suggest that communities with industrial history or proximity to fire training facilities warrant closer attention. Illinois adopted a 2 ppt advisory level for PFOA in drinking water, among the nation's strictest standards, but enforcement at the county level varies by system size and funding capacity.
Private well owners should test annually for nitrate and bacteria, with additional testing for lead if the home has older plumbing. Municipal water customers can request their utility's most recent Consumer Confidence Report to understand local testing results and any ongoing violations. Check your water for current contamination data in your area, review our water filter guide for treatment options suited to specific contaminants, request your detailed report for comprehensive testing history, or visit the Illinois state page for broader regulatory context.
Drinking water is one exposure route. These federal datasets also cover Macoupin County, IL.
The EPA places Macoupin County, IL in Zone 2 - a moderate-risk category, with a predicted average indoor radon level between 2 and 4 pCi/L. Zone maps predict an area's radon potential from geology and existing indoor readings; they say nothing about a specific house. Testing is the only way to know your own level.
69% of homes in Macoupin County, IL were built before 1980, and 35% before 1950. Residential lead paint was banned in 1978, so housing age is the strongest available proxy for lead-paint exposure. This describes the county's housing stock, not any one home.
Modelled annual fine-particle pollution (PM2.5) in Macoupin County, IL averages 8.4 µg/m³, within the EPA's annual standard of 9 µg/m³. These are CDC modelled county estimates rather than readings from a specific monitor.
How radon zones work · Air quality by county · Lead exposure guide
7 public water systems serving Macoupin County, IL have EPA lead testing on record. The reported lead sample skews toward systems that already flagged a problem, so its exceedance rate is not directly comparable with other areas. 3 water systems serving Macoupin County, IL carry a health-based EPA Safe Drinking Water Act violation.
| Most-cited violation type | Systems affected |
|---|---|
| Lead and Copper Rule Revisions | 1 |
| Interim Enhanced Surface Water Treatment Rule | 1 |
| Total Organic Carbon | 1 |
| Lead and Copper Rule | 1 |
Source: EPA Lead and Copper Rule 90th-percentile tap sampling and EPA SDWIS Safe Drinking Water Act enforcement records, aggregated from the public water systems serving this county. Figures are counts of water systems, not a test of any individual home or tap.