How to Back-Flush a Pool Pump

backyard inground pool
  • 2 hours
  • Beginner
  • 1

If your swimming pool equipment is configured the way most are, then your pool pump is set to run for a couple of hours every day, usually during off-peak hours. The pool pump is what circulates water through the pool, the various water lines, the heating system, and the filtration system. The filtration systems of most swimming pools aren’t self-cleaning, so they need to be backflushed from time to time. Recommendations on the correct frequency of backflushing will depend on who you talk to and what kind of filtration medium your pool uses. There are a number of different types of pool filtration systems on the market. Each of them has slight differences in the methods employed in backflushing the pool pump and filtration system. Below you will find the steps needed to backflush a standard pool filtrations system using silica sand as the filter media.

Tools Required

Most pools won’t require any special tools for this beyond your hands. However, when servicing some older pools, you may need a pair of pliers to move the valves around.

Step 1 - Turn Pump off

You should never move any valves or make any changes to pool operation with the pool pump operating. This includes changing the hours of operation but is especially important when moving valve positioning.

Step 2 - Turn Main Control Valve to Back Flush or Clean

This reverses the flow of water through the pool pump and filtration system, washing the debris and contaminants out of the system and restoring the filtration qualities of the filter media. Some valve systems require you to push down on the valve in order to turn it, while others require you to lift up on the valve handle. There are also some valves that require you to squeeze a handle to unlock them for movement.

Step 3 - Turn the Pool Pump Back on

man removing a pool filter

Once the pool's valves are in the proper backflush positions, you need to turn the pool pump back on, causing water to flow in reverse through the filtration system and thus washing the dirt and debris from the filter. Some pool pumps have a sight glass on them which allows you to see the water as it moves through the pump. Watch this sight glass. When the water in it is flowing clear and you see no contaminants in the water, you can turn off the pool pump, reset the valves for normal pool pump operation, and turn the pump back on. If your pool pump or filter isn’t equipped with a sight glass, you will need to run the pump for approximately one minute, and if your pool pump has a backflush outlet, watch the outlet for when the water flows clean.

Step 4 - Turn Pump off

backyard swimming pool

Once the backflush is complete, you need to reset the control valves to normal. Before you can do that, you need to shut the pool pump off.

Step 5 - Reset Pool Valves to Normal Operation

Push, pull, or squeeze the valve handle to release it and turn it back to normal operation.

Step 6 - Turn Pool Pump on

Once the valves are reset to normal, you may turn the pool pump back on.