Most wells in valley bottoms in the eastern half of the county are adequate for a domestic supply. In the western half of the county groundwater becomes more scarce; less than half of the wells drilled in valley bottoms are able to produce enough water for a domestic supply. Throughout the county, wells on hillsides and ridges are progressively less productive the farther they are from the valley bottoms. Quite a few high volume wells ( more than 50 gallons per minute) are found along the Ohio River alluvium in northern Greenup County. Most of the water from drilled wells is very hard to extremely hard and contains noticeable amounts of iron. Salty water is commonly found in wells drilled less than 100 feet below the level of the principal valley bottoms. A few springs supply sufficient quantities of water for domestic use. Almost all springs yield less than 5 gallons per minute.