Hydraulic Engineering Standards & Calculation Methodology
WellPumpSizing.com is an open, deterministic calculation utility built to eliminate guesswork from submersible water well sizing, protect pump motors from premature burnout, and guarantee adequate household water pressure.
Hydraulic Institute & Water Systems Council Standards
Calculations on this platform adhere strictly to established equations published by the Hydraulic Institute (HI), the National Ground Water Association (NGWA), and Franklin Electric:
- Hazen-Williams Friction Equation: Models real-world fluid dynamics through poly pipe (C=150), PVC (C=150), and galvanized steel (C=120) with a standardized 10% fittings allowance for pitless adapters, elbows, and check valves.
- Total Dynamic Head (TDH): Calculates the total energy required to deliver water by summing vertical pumping lift, pipe friction loss, elevation rise, and discharge pressure head (1 PSI = 2.31 ft of water).
- Hydraulic to Motor Horsepower: Calculates theoretical Water Horsepower (WHP = (GPM × TDH) / 3960) and applies empirical pump mechanical efficiencies to recommend standard NEMA motor sizes with safe service factor margins.
- Boyle's Law Pressure Tank Sizing: Sizes pre-charged diaphragm tanks to ensure the pump runs for a minimum of 60 to 120 seconds per cycle, preventing short-cycling heat fatigue.