How to backwash a pool

Backwashing is a method of cleaning a swimming pool filter by reversing the flow of water. It should be done until the waste line is completely free of sewage.

A filter cleansing technique that involves reversing the flow of water into your filter device is followed. Most pool filters work by forcing water through a porous medium (usually sand) and delivering clean water back to the pool; however, larger particles accumulate throughout the filter over time.

Backwashing your filter media, whether it’s Zeoplus, sand, glass pearls, or diatomaceous earth entails reversing the flow of water via it (DE). This flushes dirt and debris out of your multiport valve waste line, dislodging any that could have been stuck.

As a result of the increased strain, the filter’s effectiveness is reduced, and even lead damage occurs.

Washing frequency

The duration of backwashing is largely determined by the amount of usage your pool receives, as well as the type of filtration device and its location. If your pool is surrounded by shrubs or trees, it will probably need more frequent backwashing than a pool that isn’t exposed to leaf litter or organic debris. Backwashing your pool should be done once a week or in conjunction with your regular maintenance. When your filter’s pressure scale reads 8-10 PSI (pounds per square inch) above the starting level or “clean” pressure, it’s time to backwash. If your filter is usually operating at 15 PSI but suddenly rises to 25 PSI, you can backwash it.

Recycling dirt

If soil or DE (diatomaceous earth) gets into the pool through the filter, look for Grids, laterals, or cartridges that have been damaged, retainers or broken manifolds, and Poor gaskets or O-rings on backwash valves. The importance of maintenance and prevention cannot be overstated: Perform a teardown and lubrication before any leaks occur if you notice a backwash valve being difficult to switch. When you disassemble a filter for cleaning, inspect the grids, laterals, cartridges, and manifolds carefully. When reassembling, don’t rush most filter leaks are caused by sloppy and careless reassembly after cleaning.

How to backwash a pool and filters

Although each filter can keep your pool clean, the secret to cleaning it up is to make sure it is the right size and is cleaned regularly. Since they are simple to maintain, cartridge filters are a common option. Choose a filter that is appropriate for the size of your pool. When a full teardown and cleaning aren’t possible, backwashing a DE filter should be found as a temporary solution. Backwashing works well with a sand filter. In case, there is no DE to apply, there is no risk of errors resulting in a dirty pool.

Backwashing equates to good filtration because it helps to maintain a high standard of pool water. Filtration prevents cysts and bacteria from causing waterborne diseases. Backwashing is also a quick and easy practice that can save you money and time. Backwashing takes just a few minutes, but it absorbs approximately 200 to 300 gallons of pool water in a standard pool! As a result, your pool is losing a lot of water while your filter is removing unnecessary dirt and debris. And that’s just for one backwash. The average cost of maintaining a swimming pool is $229 for a one-time cleaning.

How to backwash a pool filter

Instructions differ depending on the filter type; if appropriate, check the filter manufacturer’s website. This is how it’s achieved with a DE filter in general:

Turn the backwash valve (plunger or multivalve) to the backwash setting after turning off the pump and filtration device.

Restart the pump until the filter viewing window is clear. To extract more DE, alternate backwash and clean (or filter for plungers) a few times. When adjusting valve settings, remember to switch off the pump. You can see water flowing through the view glass by switching on the pump.

To clear the DE, substitute backwashing and rinsing a few times. When adjusting the value settings, try to switch off the pump. Some units have a DE separation tank that catches and contains the DE. DE can be thrown away in the garbage.

While the filter is being disassembled, switch off the pump to ensure that the timer or automation system does not turn back on. To do so, you will need to modify the timer configuration.

Flush the filter by releasing the water through the release valve at the top of the filter. Remove the drain plug at the base of the filter (sometimes with a screwdriver) to allow the water to drain quite properly from the tank’s base.

After cleaning the filter, operate the pump at a slow rpm to conserve energy. This can be accomplished without hitting a no-flow or low-flow state.


When running a backwash or resetting the filter valve, ensure your pump is switched off. If you fail to do so, you risk causing harm to your device or even destroying it, which would be a costly mistake.

Backwashing can lead to water loss. Although this cannot be avoided, you can reduce the amount of water wasted by not overdoing the backwashing operation. Observe the water’s color via glass and stop as soon as it turns transparent.

You’ll probably rinse out a few of your sand, including the debris and gravel, mostly during backwash. This will necessitate replenishing the sand in the filter. When topping up your pool, run the filter system on the rinse setting for a minute to reduce sand blowback.

If your backwash valve becomes difficult to switch, it is suggested that you break it down and moisturize it before any leakage develops.

Examine all of your components, including the cartridges, grids, and laterals, when reconfiguring your filtering system after backwashing. Don’t hurry the installation because this is when most filter leaks occur.

Leave a Comment