If you are in the in the swimming pool industry or have a swimming pool, there’s a pretty good chance your swimming pool will have a sand filter. This is not to say that you could have a cartridge or DE filter but the most common filter for both residential and commercial swimming pools are sand filters. They are simple to use, require the least amount of maintenance and for the most part, do a great job at keeping your swimming pool clean and clear! From a price point, they are usually the least expensive filter as well. All of these reasons make it the first choice for many when they need to pick out a filter for their swimming pool. With this blog post, we would like to highlight the benefits of a sand filter, why your pool might need a different filter, how to backwash them and what to look for when the filter needs to be replaced.

How Do Sand Filter Work?

As the water flows down through the bed of sand, dirt and debris get trapped.  When the clean water exits through the bottom of the filter, it is then returned to the pool through lateral tubes at the base of the filter. Please keep in mind, sand filters do have some limitations.  Sand can filter debris down to approximately 20 microns and anything smaller probably will not get filtered out.  This is why if you have a plaster pool with very little vegetation (trees, bushes, leaves etc.) in the backyard a sand filter will work just fine for you. However, the more vegetation you have along with pebble tec pools we recommend cartridge (great for water conservation) or DE filters for higher levels of filtration needed.

When and How Do I Need To Backwash Them?

  1. First, attach a long enough backwash collapse-able hose to the waste or backwash port of your sand filter
  2. Turn your filter system off and switch the valve to the “backwash” position
  3. Turn your filter back on and let the water rush out of the backwash port and through the backwash hose for approximately a minute or until the water starts to run clear
  4. When it is finished turn your pool filter system off and turn the handle back to the filter position.
  5. Turn your filter back on and rinse your filter for about 30 seconds.
  6. If your swimming pool hasn’t been back washed for awhile, you can repeat steps 2-5 again until the water is clear.


Typically, you will want to backwash your swimming pool when the pressure gauge gets to 7-10 psi above the starting point.

When Do I Need To Replace The Sand Or Filter?

The following are reasons why the filter might need to be replaced:

  1. It’s noisy
  2. It’s leaking
  3. The pool isn’t staying clear
  4. The filter continues to run at high pressure even after backwashing

The following are reasons to change the sand:

  1. When you open up the filter check to see if channeling has occurred or if the sand is clumpy
  2. If you see sand on the bottom of the pool (this usually means a cracked lateral)

On average, sand will usually last 5-7 years! If you should have any questions about makes and models of sand filters or how they work, contact us today!