How Often Should I Backwash My Pool?


Backwashing your pool is essential to the health of your filter and your pump. Regular backwashing and proper maintenance can help you get the most out of your pump.

Experts recommend that you backwash your pool at least once a week, normally after vacuuming. If you begin to lose suction when vacuuming this may indicate the need to backwash. You may need to backwash more often if there are lots of trees nearby.

Pools require a lot of maintenance to run at peak performance, and backwashing is a part of that. Read on to learn more about this necessary procedure.

Backwash Weekly and As Needed

It is best to backwash your pool once a week to keep the filter clean. Most people do this right after they have vacuumed their pool. This helps to keep down debris that might clog the filter.

Pools should also be backwashed after heavy rainstorms. The storms are likely to fill the pool with twigs and leaves, especially if there are trees near your pool. These will clog your filter and cause myriad problems. Backwashing will help to rid the pool and the filter of debris thrown in by the storm.

It is also a good idea to backwash your pool after an algae outbreak. While the backwash cannot eradicate the algae itself, it will help to remove any remaining traces in the filter once the algae outbreak has been treated by the proper methods.

If you begin to lose suction while vacuuming then this may also mean you need to backwash. Check the pressure gauge on the filter and if it is higher than normal this means there is too much back pressure so go through the backwashing procedure.

In addition to these guidelines, your pool may need to be backwashed more often if you live in a dusty area or have many trees in the yard. These conditions will expose your filter to greater levels of debris which may necessitate cleaning it more often.

How Often Should I Backwash My Pool

Can You Backwash A Pool Too Much?

You don’t need to backwash your pool just for the sake of backwashing. If you keep up with your weekly backwashing and vacuuming, your pool shouldn’t need too much more.

You can also decrease the backwashing frequency by keeping a cover over your pool when it is not in use. This will keep out leaves, twigs, and other debris that would need to be removed by your filter. An ounce of prevention is worth a pound of cure, so covering your pool may be the best thing you can do for your pump.

It will keep out the debris that would otherwise clog your filter, so your equipment won’t have to deal with it in the first place. This will reduce the amount of junk that your filter has to remove from the pool.

Generally, if you use a solar pool cover, this will not prevent dust and debris entering. This is because you will need hose off the cover before rolling it up so whatever is on the cover will enter the pool.

What Exactly Is Backwashing?

Backwashing reverses the water flow to clean out debris that has become lodged in your pool’s filter. Filters collect all the messiness that accompanies pools. In return, they become clogged with a large portion of the mess they collect.

Small stones and twigs can become lodged in the filter, which makes it have to work harder.  When the filter has to work harder, the pump has to work harder. Backwashing helps to dislodge the caught debris and send it down the drain.

This keeps your filter clean longer and helps to extend its life.

How To Backwash

Backwashing is not a difficult job that just involves switching the pump on and off at various times when you change the settings on the multiport valve. To backwash your pool, follow these steps:

  1. Turn off the pump
  2. Set the multiport valve to “backwash”
  3. Roll out or attach backwash hose to filter
  4. Turn on the pump
  5. Run until water is clear in the viewing tube
  6. Turn pump off
  7. Set multiport valve to “rinse”
  8. Turn pump back on for 30-60 seconds
  9. Turn pump off
  10. Return multiport valve to the “filter” setting
  11. Roll up or detach backwash hose from the filter

If your filter is the DE (diatomaceous earth) type, some of the DE may be washed out in the backwashing process. Be careful to replace this so that your filter can function at peak capacity.

For full backwashing instructions, with pictures, read my article How to backwash a filter, step by step.

What Happens If You Don’t Backwash?

When debris becomes embedded in the filter, the pump has to push harder to get water through the filter. This increases pressure on the pump. Over time, this increased pressure will take its toll on the pump and it will also mean you will begin to lose suction in your pool vacuum.

Constantly having to push harder and harder against increased resistance will cause the pump to fail prematurely. The heat from the increased workload of the pump may cause it to burn out.

If you do not backwash your pool regularly, your filter will fail to clean the water properly because it has become so clogged, it can’t hold anymore. Your electric bill will also go up because the increased energy needed to push water through the filter will make the pump pull more electricity.

On top of that, if you never backwash your pool, your filter won’t be able to do its job properly. Therefore, your pool water will not be clean. This can allow an outbreak of algae and bacteria to infest your pool. That means that the water your family plays in will be full of harmful organisms that can make them sick.

Since these organisms enter the body primarily through the nose, your kids will potentially be picking up loads of bacteria to invade their sinuses and cause infections of all kinds.

You can avoid these unpleasant situations by simply backwashing your pool once a week. 

Where Does The Water Go After a Backwash?

Where Does The Water Go After a Backwash

You have a few options to dispose of the backwash water, such as:

  • If your city officials are okay with it, you could channel it into a storm drain. This would allow it to collect with the rainwater that drains off the streets. But be sure you ask for permission first, or you might find yourself paying a whopping fine.
  • If there are dry wells in your area, you could drain the water into them. They would reabsorb it into the groundwater system, where it would be purified by the rocky layers of earth. Again, be sure your city or county officials have no problem with this.
  • You might be allowed to drain the backwash water into a plumbing clean out. This would drain the water into your city’s septic system. As always, you would need the city’s permission because if your pool is huge, it might overwhelm your city’s septic system.
  • If you live in a rural area, you can build a sort of trench lined with stones. The backwash water can be disposed of there, much like a septic absorption site.
  • If you have hardy plants, backwash water can be reused as irrigation.

Be careful not to dispose of it anywhere near streams of water or vegetation that you don’t want to kill. Remember, pool water contains high levels of chlorine and salt, as well as sunscreen residues and other contaminants.

These substances are harmful to the environment and can damage vegetation, in addition to contaminating water sources.

Backwashing Clears Things Up

Anytime you notice your pool water getting cloudy, you need to backwash your pool. Cloudy water means that your filter isn’t doing its job correctly. That is usually because your filter has too much residue trapped inside.

You don’t need to backwash for extended periods; two or three minutes is usually enough. When the water becomes clear, you can shut it off. This will keep your pool clean and healthy for your family to enjoy those summer evening swims.

Poolside days are more fun when the pool is sparkling clean.

Pool Maintenance Course

When I first bought my house with a pool I knew nothing about how to clean and maintain it. I was recommended Swim University’s Pool Care Handbook so I bought it and have never regretted it. It was probably the best money I spent that year as I have saved thousands by dong it myself.

Pool care handbook

JP in Fuerteventura

I have had hot tubs for many years and a pool for the last 7 years. I had to learn how to clean it, maintain it and fix it the hard way. Since then I have helped many friends and neighbors with their pools and now I want to share everything I have learned with you.

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