Quick Answer
To calculate GPM needs for a jet pump system, determine the total daily water usage in gallons, then apply a factor to account for the system's efficiency and pressure drop. A common rule of thumb is to multiply the daily water usage by 0.75 to 0.9. This will give you the required GPM.
Calculating Daily Water Usage
To determine the daily water usage, consider the number of people in the household, the number of animals, and any irrigation needs. For example, a family of four with two animals and a small garden might require 200-300 gallons per day. Apply this number to the factor mentioned above to get a more accurate GPM requirement.
Factors Affecting Jet Pump Efficiency
Jet pump efficiency is affected by several factors, including the well depth, water table elevation, and pipe diameter. A well with a shallow water table (less than 20 feet) and a small pipe diameter (less than 1 inch) will require less GPM than a well with a deeper water table (over 50 feet) and a larger pipe diameter (over 2 inches). Consider these factors when applying the GPM calculation.
System Design Considerations
When designing a jet pump system, consider the static water level (SWL) and the total dynamic head (TDH). The SWL is the distance from the water table to the pump, while the TDH is the sum of the SWL and the headloss in the pipes. A common rule of thumb is to ensure the system is designed for a TDH of 25-50 feet. This will help prevent excessive energy consumption and system failure.
Find more answers
Browse the full Q&A library by topic, or jump back to the topic this question belongs to.