Service inlet also means storage tank inlet.
Standing or Static water level - distance from top of well to
natural water level when pump is not operating.
Drawdown distance - distance water level drops while pump is
operating.
Drawdown level - standing water level plus drawdown.
Submergence - distance submersible pump intake screen is
installed below drawdown level.
Elevation - vertical distance between top of well and service
inlet.
Pump setting - distance from top of well to pump inlet screen.
Pumping level - distance from drawdown level to service inlet.
Service pressure - pressure (in PSI) at service inlet.
Friction loss - loss of pressure due to friction of water flowing
through pipe and fittings.
Total discharge head - discharge head (in feet) delivered
when pump is operating at desired capacity.
Horizontal pipe run - horizontal distance between service
inlet and well.
Note: PSI can be converted to equivalent feet of head by
multiplying by 2.31.
HOW TO SELECT THE CORRECT PUMPING
EQUIPMENT
The answer to four basic questions will help select the
proper pump.
1. WHAT IS THE SIZE OF THE WELL? The inside diameter of the well must be known so that the proper size
pump, injector, cylinder or drop pipe and foot valve can be determined.
2. WHAT IS THE PUMPING LEVEL? The vertical distance in feet from the pump to the water level while the pump
is operating. If the pump is installed away from the well and is on higher ground, this elevation must also be
included. Most wells draw down while being pumped so this must not be confused with the standing water level.
3. WHAT SHOULD BE THE AVERAGE DISCHARGE PRESSURE? Usual average discharge pressure is 40 lbs -
halfway between the 30 lbs to 50 lbs switch setting of most water systems. When the tank is installed away from
the pump at a higher level, or when house or yard fixtures are above the pump and tank, a greater pressure is
needed and a larger pump must be used.
4. WHAT CAPACITY IS REQUIRED? The discharge capacity of the pump in gallons per hour that is needed for
satisfactory service. The pump should have enough capacity so that it can deliver the total water requirement in 2
hours of continuous operation. See table of water requirements below.
| Each person, per day, for all purposes (this is an estimate based on 1983 tables. Current estimates double this requirement) |
50 gal |
| Each horse, dry cow or beef animal |
12 gal |
| Each milking cow |
35 gal |
| Each hog per day |
4 gal |
| Each sheep per day |
2 gal |
| Each 100 chickens per day |
4 gal |
| Drinking fountain, continuously flowing |
50 to 100 gal per day |
| Each shower bath |
Up to 60 gal |
| To fill bathtub |
30 gal |
| To flush toilet |
6 gal |
| To fill lavatory |
2 gal |
| To sprinkle 1/4" of water on each 1000 square feet of lawn |
160 gal |
| Dish washing machine - per load |
3 gal |
| Automatic washer - per pad |
Up to 50 gal |
| Regeneration of domestic water softener |
50-100 gal |
| Shower |
4 to 6 gallons per minute |
| Bathtub |
4 to 8 gallons per minute |
| Toilet |
4 to 5 gallons per minute |
| Lavatory |
1 to 3 gallons per minute |
| Kitchen sink |
2 to 3 gallons per minute |
| 1/2" hose and nozzle |
200 gallons per hour |
| 3/4" hose and nozzle |
300 gallons per hour |
| Lawn sprinkler |
120 gallons per hour |
