If water must be drawn from a well by hand or carried from a spring, each person uses only about 2 gal/day, but good sanitation is difficult. For a pressurized water system, a supply of 1-2 gal/min is minimal because a single faucet discharges about 2 gal/min; 6-8 gal/min is better for a water-cooled heat pump and for watering stock and a garden. A roof downspout leading to a cistern was popular in earlier days because this water was close to the house. However, the stored water was usually inadequate during droughts. Also, dead insects and bird droppings on the roof contaminated the runoff, and open containers bred mosquitoes and algae. Few people use cisterns today.
When early pioneers were selecting land and a home site, a place for a water mill was the first consideration, but a perennial spring was the second. A good spring is a gift of nature and should be treasured and protected.