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Well Pump Size Calculator

Who it's for: Well and plumbing contractors, service technicians, and estimators.

This Well Pump Size Calculator page is designed as a practical planning resource for well and plumbing contractors, service technicians, and estimators.

Calculator Inputs

Next Steps

  • Start with realistic fixture/demand assumptions and validate against code methods.
  • Check pressure, flow, or slope implications before locking design direction.
  • Record assumptions for permit and field coordination follow-through.

Worked Example

Worked example: use your real project inputs, run at least one conservative scenario, and compare outputs against one related calculator before finalizing direction.

Detailed Explanation

Converts cut-out pressure to feet of head using 2.31 ft per psi for a worst-case tank-pressure target. Builds lift head from pumping water level plus elevation to the highest fixture and adds estimated friction losses. Applies a safety factor and maps resulting TDH plus flow demand to a heuristic pump HP class.

  • Converts cut-out pressure to feet of head using 2.31 ft per psi for a worst-case tank-pressure target.
  • Builds lift head from pumping water level plus elevation to the highest fixture and adds estimated friction losses.
  • Applies a safety factor and maps resulting TDH plus flow demand to a heuristic pump HP class.

Common Mistakes

  • Ignoring run length or pressure constraints when sizing lines.
  • Using generic fixture assumptions that do not match actual use profile.
  • Skipping local plumbing code verification.

FAQ

TDH is estimated from lift head, pressure head, and user-entered friction losses, then adjusted by a safety factor.

Cut-out pressure is used as a worst-case operating target so the estimate reflects higher required head conditions.

No. Final model selection requires manufacturer pump curves and verified field conditions.

High-head scenarios should be validated with detailed pump-curve analysis and often require more specific system design.

When to Call a Professional

Call a licensed plumber when outputs influence final installation decisions or permit submissions.

Related Calculators

Sump Pump Size Calculator

Estimate required sump pump flow with safety margin and suggest an initial HP class for planning checks.

Pipe Volume Calculator

Calculate pipe internal volume in gallons, liters, and cubic feet from diameter and run length for planning and flushing estimates.

Conclusion

Use this estimate to improve planning speed and communication, then validate final values against code and manufacturer data.

About This Calculator

About this calculator: Well and plumbing contractors, service technicians, and estimators.

Educational and planning use only. Verify final values with licensed professionals.

Written by BuildCalcTools Team - Plumbing planning guidance.

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