Residential Well Sizing Guide

What Size Well Pump Do I Need?

Selecting the correct well pump requires balancing two numbers: Flow Rate (Gallons Per Minute / GPM) to satisfy peak household fixtures, and Horsepower (HP) to overcome depth and pressure resistance.

Avg Home: 8–12 GPM | Homestead: 15–20 GPM
ft
Static level + drawdown under continuous pumping
ft
Vertical climb from wellhead to pressure tank
ft
Trench length from wellhead to house
RECOMMENDED PUMP MOTOR 1.5 HP (1-1/2 HP) 1.47 HP (Shaft Load)
TOTAL DYNAMIC HEAD (TDH) 337 ft Head 3.7 ft Friction Loss
CABLE WIRE GAUGE 12 AWG Copper
BREAKER SIZE 25A 2-Pole
MIN PRESSURE TANK 37+ Gal Tank
💧 Pressure Tank Drawdown Capacity:

Min 10 Gal Drawdown (provides safe 60s motor cycle)

Deep Well Submersible Pumping System Blueprint

Cross-sectional engineering diagram: Well casing, dynamic water level, submersible pump, pitless adapter, and residential pressure tank assembly.

TDH: 337 ft Head
Drilled Well & Submersible Pump Cross-Section Hydraulic blueprint illustrating deep well casing, submersible motor, drop pipe, pitless adapter, buried waterline, and indoor pressure tank. GRADE LEVEL (SURFACE) WATER LEVEL (180′) WELL SEAL 1.25″ Poly Water Pipe PUMP MOTOR UTILITY ROOM / BASEMENT PRESSURE TANK 60 PSI TO HOME CALCULATED OPERATING POINT 10 GPM @ 1.5 HP (1-1/2 HP) Total Dynamic Head: 337 ft
💡 Pumping Point: 10 GPM flow against 337 ft Total Dynamic Head requires a 1.5 HP (1-1/2 HP) motor.

Step 1: Determine Required Flow Rate (The Fixture Rule)

The standard industry rule of thumb recommended by the Water Systems Council sizes residential flow based on total home plumbing fixtures:

  • Count every water outlet: Showers, toilets, bathtubs, kitchen sinks, dishwashers, washing machines, and outdoor hose bibs.
  • Allow 1 GPM per fixture: A home with 2.5 bathrooms, kitchen, laundry, and 2 hose bibs typically has 10–12 fixtures, requiring a 10 to 12 GPM pump.

Step 2: Match Well Recovery Rate

A pump should never be sized larger than your well's sustainable recharge rate. If your well drill log shows a recovery yield of only 5 GPM, installing a 12 GPM pump will quickly pump the well dry, drawing air and destroying the pump's impellers unless a low-yield cistern buffer is installed.

Next Steps for Sizing Your System:

Calculate your system's vertical lift resistance with our Total Dynamic Head Calculator or size your drop cable in the Wire Size Sizer.