Most wells drilled in valley bottoms are adequate for domestic use. Fewer than half the wells drilled on hillsides are adequate for domestic supply, and even fewer wells on hilltops and ridges produce enough water for a domestic supply. Wells in the southern third of the county generally produce slightly more water, perhaps enough for small municipal or industrial supplies, in wells below 200 feet. Most of the water obtained from drilled wells is extremely hard and contains noticeable amounts of iron. Salty water may be found from 50 to several hundred feet below the level of the principal valley bottoms. Groundwater quality is slightly better in the southern third of the county, with moderately hard water and salty water found occasionally in from 100 feet and deeper. A few springs supply enough water for domestic use. Almost all springs yield less than 5 gallons per minute.