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Sump Pump TDH

Calculate Total Dynamic Head (TDH) for sump pump selection, accounting for static lift and friction loss.
feet

Total Dynamic Head (TDH)

TDH is the sum of Static Head (the vertical height you are lifting the water) andDynamic Head (the friction created as water rubs against the inside of the pipe). If you use a pipe that is too small, the dynamic head will be so high that the pump won't be able to move any water at all.

Total Dynamic Head

11.6 ft
Incl. 1.6ft friction

Recommended Pump

1/3 HP
Based on TDH calculation
For estimation purposes only. Always consult a licensed professional before beginning work. Full Trade Safety Notice →
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What is Sump Pump TDH?

Total Dynamic Head tells you the total resistance a pump must overcome. If you only look at vertical height, you'll ignore the massive friction created by pipe walls and elbows.

Mathematical Foundation

Total Dynamic Head
TDH=Hstatic+HfrictionTDH = H_{static} + H_{friction}
HstaticH_{static}= Vertical Lift (Static Head)
HfrictionH_{friction}= Friction Loss from Pipe/Fittings

Laws & Principles

  • Hazen-Williams friction factors are calculated at a standard 50 GPM flow.
  • A 90-degree 2-inch elbow adds as much friction as 5 feet of straight pipe.
  • Check valves are high-friction points, adding roughly 10 feet of equivalent length.
  • Smaller pipes (1.5") create significantly more friction than larger pipes (3").
  • Always consult the manufacturer's Pump Curve once you have your TDH.

Step-by-Step Example Walkthrough

" 10ft lift through 25ft of 2" pipe with 3 elbows and 1 check valve. "

  1. 1. Static Head = 10 feet.
  2. 2. Calc Equivalent Length: 25ft + (3 elbows * 5ft) + (1 valve * 10ft) = 50ft.
  3. 3. Calc Friction Loss (2" @ 50 GPM = 2.5ft/100ft): (50 / 100) * 2.5 = 1.25 feet.
  4. 4. Total TDH: 10 + 1.25 = 11.25 feet.
Final Result: 11.25 ft TDH required.

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