How to Add Air in a Well Water Pressure Tank

Updated February 21, 2017

All well water systems use air pressure to regulate the water pressure in the system. The pressure tank may or may not have a bladder. The bladder tank uses a rubber enclosure that holds a certain amount of air pressure. The bladderless tank uses no such bladder, but keeps a column of air near the top of the tank. When air pressure is low, the water pump will short cycle on and off many times during a refilling operation. Short cycling indicates that the pressure tank is low on air and needs filling.

Shut off the electrical power to the water pump. Open a cold water faucet to remove the water pressure.

Locate the air filling valve on the water pressure tank. The air filling valve resembles the air valve on your car or truck tire. Remove the cap on the filling valve.

Check the air pressure in the system. If it is below 13.6 Kilogram per Square Inch, you need to add air into the pressure tank.

Attach the tire filler attachment from the compressed air source to the air valve on the pressure tank. If you are using a tire pump, connect the filling valve to the same point.

Fill the water pressure tank with air. Stop every so often to check the air pressure with the air pressure gauge. After the air pressure reaches the proper level, stop filling. Apply power to the water pump.

Shut off all electrical power to the water pump. Attach a garden hose to the bottom of the water pressure tank at the drain spigot. Open the drain spigot valve.

Drain the tank of all water; this will fill the pressure tank with air. Ensure the pressure tank is empty of all water.

Remove the garden hose. Close the drain valve.

Apply power to the water pump. The air inside the tank will become pressurised to regulate the water pressure. If the tank loses air pressure on a regular basis, you may have a small leak near the top of the bladderless tank.


Air pressure ranges greatly on most well water pressure systems. In almost all cases, raising air pressure between 35 to 40 PSI will allow the water pump to function normally.

Things You'll Need

  • Air pressure gauge
  • Compressed air source with tire filler (optional)
  • Tire pump (optional)
  • Garden hose
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