Does backwashing drain your pool?

Author: Savannah Upton  |  Last update: Wednesday, July 16, 2025

Backwashing can result in a loss of water. While this is unavoidable, you can minimize the amount of water you lose by not overdoing the backwashing process. Keep a close eye on the colour of the water through the view glass and stop the minute it becomes clear.

Why is my pool losing water after backwashing?

Multi-port backwash valves

have a tendency to leak water into the backwash line when the seat gasket gets worn out or the handle was not fully pressed while turning the valve to set to the backwash position.

Is it bad to backwash your pool filter too much?

Backwashing a filter too frequently will keep the sand so free of dirt buildup that it will not have the ability to remove the smaller particles of dirt and they will simply pass through sometimes causing cloudiness in water.

Does backwash send water to waste?

Backwashing reverses the flow of water, lifts up and flushes the sand, and then expels the dirty water via a waste line into the ground or drain.

Does backwashing empty the pool?

Backwashing can result in a loss of water. While this is unavoidable, you can minimize the amount of water you lose by not overdoing the backwashing process. Keep a close eye on the colour of the water through the view glass and stop the minute it becomes clear.

How To BACKWASH A POOL FILTER (The Right Way)

What happens if you don't rinse after backwashing pool?

Rinsing for 30 seconds after backwashing pushes the sand back in place clearing the filter of loose dirty water. If you don't rinse, you will have a puff of dirty water coming through the jet and back into your clean pool.

Why is backwash bad?

Backwash is the term used for fluid which makes its way from a person's mouth back into a drinking container. Why is backwash considered bad? If you're sick, you could be putting sickness causing bacteria back into the container and if someone else drinks from it, they could get sick too.

Where does the water go when you backwash a pool?

To Backwash Your Filter

Backwash water must be collected, contained and discharged to the sanitary sewer, if available, or to a vegetated area contained within your property. Cartridge filters should be rinsed in a sink, bathtub, or over a lawn or other vegetated area.

Is it better to backwash or waste?

Drain/Waste: Opting the drain or waste setting will remove pool water without forcing it through the filter. Backwash: This clears out any debris, dirt and other contaminants that may have accumulated on the filter. Closed: if you choose this setting, then the flow of water to the pool and filter will be stopped.

What is the filter backwash rule?

What is the Filter Backwash Recycling Rule? The FBRR requires filtered surface water suppliers using conventional or direct filtration to, where needed, change the return of recycle flows in their plant's treatment process.

How long can you leave a pool on recirculate?

With filter on re-circulate, run pump for 2 hours then cut pump off. 24 hours later, hand vacuum slowly to remove waste. Wait one more day as pool water may drop out additional waste during this time.

Does backwashing remove algae?

Use a vacuum or backwash the pool to remove the dead algae. Apply a mustard algaecide following the label directions. Allow the water to circulate for 24 hours. Use a pool vacuum or backwash the pool again to remove the remaining dead algae.

What happens if you backwash too much?

Backwashing too often can reduce the filter's effectiveness. The sediment layer helps improve filtration by trapping finer particles. If you backwash before it's needed, you lose this beneficial layer, which can result in cloudy water.

Why is my pool losing 2 inches of water a day?

Losing more than ½” of pool water per day indicates you likely have a leak in your pool's structure or your pool pump system. You should call your pool service for a thorough leak inspection. You might not be able to keep up with refilling your pool at this point.

How often should pool pump be backwashed?

Backwashing should be a part of your weekly pool maintenance, and the best time to backwash is after vacuuming. You may need more frequent backwashing if your pool has collected a large amount of debris or other contaminants. Birds, trees, and heavy rains can make your pool prone to require more frequent backwashing.

How much water do you lose backwashing a pool?

All over the world, millions of sand filters are regularly backwashed to clear out the dirt that has accumulated in the course of normal operation. This sand filter flushout process may use 200 gallons of water or more, depending on who is doing it and how long it takes to run clear.

What is the ideal level of chlorine in a swimming pool?

Regardless of how frequently or what system you use to add chlorine to the water, the chlorine level should stay between 1.0 and 3.0 parts per million (ppm) to maintain a healthy pool. Anything higher will make you run the risk of red eyes and swimmers itch.

What is the proper way to backwash a pool?

How to Backwash a Pool Sand Filter
  1. Step 1) Turn off the pool pump.
  2. Step 2) Set the filter valve handle to the 'Backwash' position and ensure the handle locks in place.
  3. Step 3) Turn the pump on and backwash for 3-5 minutes or until the water in the sight glass (located on the filter) is running clear.

How to tell if someone backwashed?

We can prove backwash happens by putting powdered drink mix in our mouths to color the saliva! The color swirling around in there proves a little of your spit goes back in your drink! That's my backwash!

Can you over filter a pool?

Well, the answer is a definite yes. But for maximum efficiency and flexibility, we suggest that you go with a large filter and a variable speed pump so that not only would you be maximizing the filter's efficiency, but you'll have the option of running the pump at faster levels during heavy days.

What problem is created by too high a backwash rate?

If backwash rates are too high, significantly more media could be lost— compromising filter performance. In any case, it is important to measure, track, and replace any missing media during your annual filter inspection and maintenance check.

Why does my pool get cloudy after I backwash?

You should backwash most sand filters every 2 weeks during winter and every week during summer. This also applies to cartridge filters as well. However, backwashing more frequently than this can lead to excessive sand loss, cloudy water, and poor filtration.

What happens if you vacuum your pool on backwash?

Most of the dirty and other foreign particles that enter your pool's system will end up here. But the dirt that accumulates at the bottom of the pool does not go to the filter. Backwashing a filter will lead to your pool being dirty temporarily. For a clean pool, do not backwash your filter before vacuuming.

Where does the water go when I backwash my pool?

To backwash via the waste line is to run your pool water back through the filter, but rather than circulating the water back into the pool, it is flushed out through the waste line. Whilst the backwashing process is flushing out the dirt and debris, so is it flushing out your water with it.

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