Connecting your residence to well water involves considerations beyond
merely digging the well. The pumping system utilized, the well capacity
and correct sizing of that system to your home’s needs all affect
your ultimate satisfaction.
Shallow-well systems, the most common, are used in wells with depths around
25 feet and normally incorporate a jet pump located at ground level, drawing
well water up through a suction pipe. Proper sizing involves determining
your household’s peak water demand, then matching a pump with sufficient
volume and pressure while not exceeding your well’s water capacity.
The simplest method of estimating household water needs is by fixture
count. The pump’s capacity in gallons per minute (GPM) should equal
the total number of water fixtures in your home — faucets, bathtubs,
The second method calculates peak demand at hours of the day when usage
is highest. The average GPM flow rate of all fixtures for a seven-minute
span during peak hours is totaled. The total figure is divided by seven
and matched with a pump that supplies an equivalent GPM.
A well that can’t produce water fast enough to keep up with the
GPM demands of your household will run dry unless well capacity is taken
into consideration while sizing. Where well water is insufficient, the
pump is sized according to the existing capacity, and the deficit —
the difference between well capacity and house demands — is made
up by installing an inline pressurized storage tank in the house.
The distance between the well and the house and the water pressure demands
of various appliances determine optimum pump pressure. Generally, the
inlet side of the plumbing fixture located farthest from the pump in the
household plumbing system should have a water pressure of at least 20
psi. Well water pressure is also affected by factors such as the condition
of plumbing and the depth of the well.