To maintain the cleanliness of your swimming pool by removing debris and dirt from its filter, it is necessary to run a backwash regularly. However, some pool owners worry that backwashing might cause them to lose water and drain out their pool. In this article, we will explore how backwashing affects your pool’s water level and how that impacts the operation of your robot pool cleaner, pool vacuum, and other pool cleaning systems.

What Is Backwashing and Why Is It Necessary?

Backwashing is the act of reversing the water flow through your pool’s filter to clean it. Over time, debris—dirt, algae, oils, liquids, etc.—builds up in the filter, and backwashing removes this debris. When the filter has been backwashed, it will return to standard functionality with the water running through it, again cleaning the pool.

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Although necessary for pool maintenance, backwashing has the downside of sending water out of the system. But does that mean it’ll suck your pool dry?

Does Backwashing Empty Your Swimming Pool?

In most pools, backwashing does not empty the pool. However, it does cause some water to be evacuated from the pool’s filtration system, which can slightly lower the water level. Let’s examine how much water is lost in backwashing and what affects this.

How Much Water Gets Wasted During Backwashing?

The amount of water lost in backwashing depends on a few factors:

  • How Long the Backwash Is On: The longer it runs, the more water it pushes out. Generally, backwashing takes 2–3 minutes and removes about 2-3% of the total volume of the pool water. For larger pools, that would translate to losing several hundred gallons of water.
  • Pool Size: The larger your pool, the more water will be used in the backwashing process. However, the proportion of water lost will be smaller for a smaller pool.
  • Filter Type: The amount of water used when backwashing varies depending on the type of pool filter (sand, DE, or cartridge filter). For instance, sand filters consume more water than DE or cartridge filters.

Will It Drain Your Pool?

Although you remove some water when you backwash, this won’t drain your pool unless you do it excessively or for an extended period. For most pool owners, backwashing every few weeks or when there is a significant pressure spike will cause little water loss. You may add a few hundred gallons to replenish water lost to backwashing, but this will not drain the entire pool.

Ways to Reduce Water Loss from Backwashing

If you’re worried about losing water while backwashing, here are a few things you can do to mitigate the effect:

  • Use a Pool Vacuum or Robotic Cleaner:
    If you use a robot pool cleaner, such as the Beatbot AquaSense 2 Pro, or a swimming pool robot cleaner, you should use it more often to clean your pool to reduce the frequency of backwashing. A pool robot can help remove debris before it clogs your filter, exerting less pressure on your system and reducing the need to backwash as frequently. A clean filter will use less water to keep it cleaner of dirt.

  • Filter Pressure and Regular Checks:
    Filter pressure increase is one of the most common reasons for backwashing. Regularly checking the filter pressure will tell you when to backwash. By doing so, your system will not backwash unnecessarily for a minimal pressure increase, thus avoiding water loss.

  • Use a Skimmer:
    A skimmer can aid in lifting floating leaves and debris before they sink and get stuck in your filter. Skimming your pool regularly decreases the quantity of debris that reaches the filter, so you won’t need to backwash it as often. That will allow you to maintain your water levels.

  • Use a Pool Cover:
    Covering your pool can minimize debris in the pool and, subsequently, backwashing. The less debris in the filter, the less water is lost while cleaning.

Can You Avoid Backwashing?

Although backwashing is an integral aspect of pool upkeep, some alternatives can help you do without it in certain situations. For example:

  • Manual Cleaning:
    Using a pool vacuum cleaner or pool vacuum robot will put less stress on your filter, prolonging the time between backwashing. Vacuuming is another routine task that keeps your pool clean and debris-free.

  • Acid Wash the Pool:
    If your pool filter is stuffed, it might be necessary to do an acid wash to clean it up. This process only needs to be done occasionally, as it involves draining some water from the pool.

  • Pool Booster Pump:
    If your pool is equipped with a booster pump, maintaining its suction level can enhance the impact and efficiency of your robot pool cleaner and pool vacuum. This can minimize debris accumulation within the filter and thus limit the requirement for backwashing.

Does Backwashing Impact Pool Robots?

Unlike a suction-side pool cleaner, using a robot pool cleaner will not be affected by backwashing, as the robot does not rely on its use with the filtration system to clean the pool. On the other hand, if you leave backwashing too long, the robotic pool cleaner or pool vacuum robot may run into debris that the filter can no longer effectively handle. To ensure the system operates optimally, you must perform a backwash when appropriate and keep the filtration system in good operational condition.

Conclusion

Backwashing will not drain your pool but will waste a little bit of water with each backwash, which can add up over time. The upside is that you can reduce water loss and keep your pool in peak condition with proper pool maintenance, including investing in a robot pool cleaner (the Beatbot AquaSense 2 and the Maytronics pool cleaner are great options) and regularly monitoring your pool’s filter. Minimizing the need for backwashing through regular vacuuming and skimming will help you retain a cleaner pool while minimizing unnecessary water loss.