Water Use

• The size of a well tank depends on the purpose of the water, such as typical home use, irrigation, farming and sprinkler systems. The Water Systems Council (WSC) indicates that the demand can be calculated in several ways. For example, you can count the total number of water fixtures in your home and multiply it by one gallon per minute (gpm). Using the peak demand calculation you should multiply the fixtures total by three gpm. A third method is to multiply the total number of bathrooms by four gpm.
  
  

Pump

• The capacity of the pump is a consideration in determining the size of the tank. The pump is also chosen based on needs. Pump capacity is indicated by gpm, ranging from four to 30, or gallons per hour (gph), ranging from 240 to 1800.
  
  

Well

• One of the purposes of a tank is to store water if the well cannot meet demands; typical well tanks hold between 15 and 120 gallons. According to WSC the capacity of a well is typically documented when it is completed. This number is represented in gph and is another important factor in determining the tank size.