1. What is a Water Well Pump Calculator?

Definition: This calculator estimates the flow rate (in gallons per minute) of a water well pump based on horsepower, efficiency, and total head.

Purpose: It helps well drillers, engineers, and homeowners determine the expected performance of a water well pump system.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Q \) — Flow rate (gallons per minute)
• \( HP \) — Pump horsepower
• \( \eta \) — Pump efficiency (decimal between 0 and 1)
• \( H \) — Total head (feet)

Explanation: The formula converts pump power to water flow rate, accounting for system efficiency and the work needed to lift water against gravity.

3. Importance of Pump Flow Rate Calculation

Details: Proper flow rate estimation ensures adequate water supply, correct pump sizing, and efficient system operation.

4. Using the Calculator

Tips: Enter the pump horsepower, efficiency (default 0.8 for 80%), and total head in feet. All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What is pump efficiency?
A: Pump efficiency (η) is the ratio of useful hydraulic power to input shaft power, typically 0.6-0.85 (60-85%) for centrifugal pumps.

Q2: How do I determine total head?
A: Total head includes vertical lift from water level to discharge plus friction losses in piping. Consult engineering tables for friction loss calculations.

Q3: What's a typical flow rate for residential wells?
A: Most homes require 5-10 GPM, but this depends on household size and water usage patterns.

Q4: Why 3960 in the formula?
A: This is a conversion factor that relates horsepower to foot-pounds per minute (1 HP = 3960 ft-lb/min).

Q5: What about variable speed pumps?
A: This calculator assumes constant speed operation. For variable speed pumps, use the maximum expected horsepower.