What Is Backwash Or Backwashing?


Your filtration system is responsible for keeping your pool’s water circulation flowing smoothly and free of impurities. However, your pool’s filtration system will only be able to do its job if it’s in good working condition. Cleaning and maintaining your pool’s filtration system shouldn’t be that difficult, especially when you use backwashing methods instead of manually cleaning them. But first, what is backwashing a pool and how does it work?

What Is Backwashing?

Much like an air conditioning unit’s filter, even the best pool filters also collect dirt over time. As the dirt builds up, the filter becomes less efficient and loses its ability to effectively filter out particles and impurities, leading to the dirty and unhygienic pool water. To keep this from happening, you need to clean the filter and remove the dirt trapped in it through backwashing.

Backwashing is the process of cleaning a pool’s filter system by reversing the flow of water to flush out the dirt and debris in it. Put simply, backwashing sends pool water backward through your filter and out to the drain port. This is a more convenient and faster way of cleaning your filter system compared to having to do it manually.

When to Backwash Your Pool

Some experts say that you should backwash your pool every two weeks, while others recommend that you do it at least once a month. In any case, backwashing should be done regularly as a part of maintaining your pool. However, there are several signs which may require that you backwash your pool ahead of your maintenance schedule.

For instance, if your pressure gauge indicates a pressure rise of 8-10 pounds above the clean or “startup” pressure, then you should consider backwashing your pool. Take note that if the pressure remains higher than normal even after backwashing, your filter may need to be disassembled and cleaned.

Also, if your filter has been running for two days straight without stopping then you will need to perform a backwash.  This is because the filtering media tends to settle onto your filter grids whenever it runs without stopping, which can cause a buildup of pressure even if your filter grids are clean.

Also, if the pool is used heavily for an extended period of time, you’ll find that it may be necessary to backwash your pool more often than usual. This is because the filter may get clogged quicker considering the number of tanning oils, sweat, and hair products that wash off from the bathers.

How to Backwash Your Pool


There are several ways of backwashing your pool. The specific instructions will vary depending on several factors like the type of filter for instance. So before you start to backwash your pool, it is recommended that you first consult your filter owner’s manual or check the manufacturer’s website for the suggested steps and procedures. In any case, the steps outlined below should apply to most DE (diatomaceous earth) filters and sand filters.

How to Backwash a DE Filter

DE Filters make use of DE powder, which are sedimentary rock composed of chemically inert, fossilized (or skeletal) remains of billions of microscopic organisms called diatoms. The DE powder coats either a cartridge, fingers or panels inside the filter which traps the dirt and other particles as water passes through it. To backwash a DE filter:

  1. Turn off the pool equipment (i.e. pool pump) at the main power switch.
  2. If you have a slide valve, turn the backwash handle and pull the valve piston straight up to the backwash position. On the other hand, if you have multiport valves, push the handle down and rotate the valve to the backwash position.
  3. Turn the pool equipment back on and run it for at least a minute.
  4. After a minute, turn the equipment off.
  5. Return the valve to the original position and turn the pool equipment on for at least a minute.
  6. Repeat the cycle (steps 1 to 5) two more times, each time reducing the backwashing time (one minute, 30 seconds, 15 seconds).
  7. After completing all three cycles, pour the appropriate amount of DE powder into the skimmer while the pool equipment is running. This will allow the DE powder to travel through the plumbing and into the filter and replace the DE powder that’s been washed out during the backwashing.

How to Backwash a Sand Filter

Sand filters use Silica Sand (not common sand) to filter the water and pull debris from the pool. Backwashing your sand filter will keep the sand from collecting too much contamination by sitting in one place for too long without being stirred up properly. To backwash a sand filter:

  1. Turn off the power at the circuit breaker to the pump before moving the multiport valve.
  2. Move the multiport valve handle from ‘filter’ to ‘backwash’ setting.
  3. Check that the backwash hose is laid out to where you want to dump the wastewater (some pool owners dump the water into their lawns).
  4. Turn the power back on and run the pool pump for at least 2 minutes
  5. Turn the power back off.
  6. Turn the valve handle to the ‘rinse’ setting to clean the filter and prevent the dirt and debris from returning to the pool.
  7. Turn the pump back on and run the filter at the ‘rinse’ setting for 1 to 2 minutes.
  8. Turn the pump off and return the valve to the ‘filter’ setting.

Globo Surf Overview

Keeping your swimming pool clean is an essential part of responsible pool ownership. So aside from getting rid of bugs from your pool, you should also make backwashing a part of your regular pool maintenance routine (especially now that you know what is backwashing a pool and how to go about it). With crystal clear waters, you and your family will have a much better time splashing around and relaxing in your pool.

More Pool Reviews: