Most ground water used in Geauga County, Ohio, is withdrawn from bedrock aquifers, chiefly sandstones of the Pottsville and Cuyahoga Formations of Pennsylvanian and Mississippian age, respectively. Two potentiometric-surface maps were constructed from water-level measurements of 77 wells and 2 springs made in June and October 1978. The potentiometric surface did not change more than a few feet between June and October except in four distantly spaced wells where water levels changed not more than 17 feet, probably due to nearby pumping.
The ground water is generally of good quality for domestic use based on guidelines set by the Ohio Environmental Protection Agency and the U.S. Environmental Protection Agency. Some water samples contained high concentrations of dissolved iron and manganese. These metals could have been contributed by deteriorating well casings, bacteria, or iron- and manganese-rich aquifer rocks.