Water Well Drilling Contractors in Illinois

Geology & Depth

Illinois is covered by thick glacial drift deposits — till, sand, and gravel laid down by multiple ice advances — which provide the primary source for shallow wells. Deeper bedrock wells tap Silurian dolomite, Cambrian-Ordovician sandstones, or the St. Peter Sandstone aquifer.

Most residential wells in Illinois are drilled to 175 feet, with a typical range of 40–500 feet. Water table depth: 20-100 feet in glacial drift; 200-1,500 feet for deep bedrock aquifers in northern Illinois.

Permits & Licensing

Illinois requires all water well drillers to be licensed by the Illinois Department of Public Health. Licensed well and pump installers must pass written exams and complete continuing education.

Permit authority: County Health Departments issue permits under Illinois Department of Public Health regulations; Illinois EPA oversees water quality. Expect $50-$200 in permit fees.

Primary Aquifer

Mahomet Aquifer (glacial sand and gravel) / Cambrian-Ordovician Aquifer System. About 14% of Illinois households use private wells, mainly in rural central and southern Illinois.

Best drilling months: March through November; winter drilling is possible but frost depths of 3-4 feet and muddy conditions slow progress.

Common Water Quality Concerns

Illinois well water commonly contains: iron, manganese, hardness, radium in deep bedrock wells, nitrate near agricultural areas. A comprehensive water test after drilling (typically $150–$500) will identify which treatments, if any, your well needs.