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How to Backwash a Pool Filter? — Clear the Last Bits of Debris In Your Pool (2021)

If you have a sand or DE filter, you may have heard of backwashing. It is a necessity! To backwash a pool, you just have to follow some specific steps.

Let's break down the results, steps, and considerations below on how to backwash pool filter.

How to Backwash a Pool Filter?

When to Backwash a Pool Filter?

Well, if you have a dirty pool, that's the biggest sign flashing in your face.

If you've recently experienced a major storm or algae outbreak, then it's time.

Turn the pump to that backwash function. Additionally, if your pool water has a lot of foliage or debris, you can backwash, too.

Importance of Backwashing the Pool Filter

Backwashing is necessary if you want to maintain sanitary pool water.

Cleaning your filter is crucial. After all, it helps keep your pool water free of calcium build-up, dirt, and debris.

Keep in mind that backwashing only applies to some filters. If you have cartridge filters, you're on the wrong page! It only helps if you have a sand filter or a diatomaceous earth (D.E) filter.

You won't need to pick through sand or earth to clean up the pool filter. Plus, regular backwashing can help keep your filter in the best shape.

D.E and sand pool filters can cost a lot. If you keep your pool equipment clean and invest in swimming pool maintenance, you get to save on having to replace your equipment.

In short, you get to enjoy clean, crystal-clear pool water for longer.

How to Backwash Your Pool Filter

Get a backwash hose and D.E powder. Be ready to invest some time to backwash your filter successfully. The D.E powder only applies if you have a diatomaceous earth filter.

If you have sand filters, you don't have to buy the powder at all.

Sand Filter

#1 Turn Off The Filter System

Turn everything off: the pool pump, filter system, and other machinery you may have. Focus on the process at hand!

#2 Attach the Backwash Hose

You should find a backwash hose online or in pool specialty stores.

Go for something that has a tapered fit, is heavy-duty, and has a hole clamp in place. Depending on the length, brand, and size, the price can start at $30 upwards.

Look for the waste port in your sand pool filter or diatomaceous earth filter. Remember, if you have a cartridge filter. Cleaning is a whole other process!

Once you find the waste port, attach the backwash hose to it.

#3 Turn the Backwash Valve On

There may be a specific valve to backwash your pool. You can turn a multiport valve to "backwash" and start backwashing your pool right away.

blue and white swimming pool

Open the air relief valve. After turning the multiport valve to the backwash option, go ahead and turn the system back on. You can let the filter stay on for a couple of minutes.

To backwash sand or diatomaceous earth filter successfully, you can use the sight glass to see how the water flow is. You want the water to run clear through the waste line.

#4 Turn the Filter System Off Again - And Rinse

This time, you're turning the multiport valve to rinse away. By now, the flow of water should be clear and clean.

Remember to turn the pool filter system off before you adjust the filter valve. Whether you're turning it to a backwash setting or the rinse setting, it has to be clear: turn off the pump and filter system.

Turn the system back on to rinse away the filter backwash water. Use the sight glass to eyeball how the water flows. Usually, around two minutes should be enough.

#5 Collect the Water

After completing the backwashing process, you have to collect and dispose of your backwash water properly.

pink floater on pool

Turn the pump off and backwash the valve. Collect the backwash water and find an area to dispose of it.

Your septic system or street drain port is a no-go. Instead, look for a vegetated area or a sanitary sewer.

As a pool owner, you can also reach out to local authorities to make sure you're disposing of everything properly. What are the normal operating standards for waste? Is there a place they recommend?

#6 Restore the Pool Filters

You're all done! Check every valve handle and make sure everything is in place. Turn the filter system back on.

Check your filters every now and then to keep your water free of dirt and debris. You can go through the entire process once again.

D.E Filter

D.E filters are one of a kind. They have filter grids and D.E powder to keep your pool water clean.

The same steps apply above.

After you backwash a pool, prime the pump. Mix the right amount of D.E with water, and put the D.E powder sludge into the skimmer.

Unlike a sand filter, you have to wait longer. Run the pool pump! You need to let the D.E powder circulate into the pool water for around eight hours.

After, you can turn off the pump and enjoy a nice swim day!

Frequently Asked Questions

How often should you backwash a pool filter?

As a general rule, you can backwash your filter every week. If you do regular maintenance work, you can add backwashing as one of the pool maintenance standards.

If you've done the whole backwash process before, there are some signs to look out for to keep the water clean.

Look at the pressure gauge first.

What's the starting level and operating filter pressure level? If the water pressure gauge reads 8-10 PSI (pounds per square inch) over that starting number, you need to backwash immediately.

How do you backwash and rinse a pool filter?

Backwashing simply involves turning the filter system off, doing a backwash function, turning it on, then turning it off again for the rinse. It's fairly easy! Refer to our guide above should you need more guidance.

The above step-by-step guide applies to the sand filter and D.E filter, but you may need to take extra steps under certain conditions.

If you have a pool sand filter, you're good to go. Sand filters are common, and you can apply our steps above.

If you're one of the pool owners that own a push-pull valve, there are fewer steps.

Turn the valve to the filter so you can turn it off properly.

After connecting the hose, open the gate. Let it pump back water and backwash. After around three minutes, you're all done! Close the valve and continue on to your day.

What is the purpose of backwashing a pool filter?

What filters out the dirt in your pool filter?

Basically, there's nothing. If your filter is full of contaminants, it won't be as efficient. The filter pressure might increase. You might end up with dirty water if you leave it be.

This is where backwashing comes in. You want clear water as much as possible.


That wraps up this how to backwash pool filter article! If backwashing isn't a regular maintenance step for you, consider checking your pool sand filter or DE pool filter, plus the pressure level.

Aside from backwashing, check up on other equipment and machinery. That includes:

  • Cleaning off your pool cover
  • See if the heater is working okay
  • Always treating the pool water with the appropriate chemicals

Backwashing is just one step into keeping your pool in the best shape.

We hope you followed this guide well! The steps are easy, and the results are worth it. After you're done, enjoy the water and swim the day away!

Read next: How to clean a green pool? This will save you time and resources when done properly. 

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