How Far Below the Skimmer Should You Drain a Pool?

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Pool skimmers are crucial parts of a pool because they draw in and trap debris that could clog the pool pump, thus interfering with the pool’s water circulation system. Therefore, when draining a swimming pool, you must consider the distance between the skimmer and the water level.

When draining a pool, maintain a distance of at most six inches (fifteen centimeters) between the water level and the pool’s skimmer. Draining lower than the recommended level interferes with the pool’s filtration system and risks costly damage to the swimming pool’s pump and motor.

Please continue reading to learn what happens when you drain a pool below the skimmer, how to drain a pool with skimmers safely, and what else you should know about properly draining a pool. You’ll also find additional safety procedures you should follow during pool draining.

when you drain a pool below a pool skimmer you interrupt the water circulation

What Happens When You Drain a Pool Below the Skimmer

The ideal water level on a skimmer is between a third and halfway up the opening. Going above or below will interfere with the skimming system. But in this article, I will focus on what happens when you drain too far below the skimmer.

Pool skimmers draw water from the top of the pool into the skimmer basket, which traps floating debris before it clogs and damages the pool’s filtration, pump, and motor systems (they are all connected).

The pool pump and motor rely on the water drawn in to cool down as the motor runs, thereby preventing damage. Draining a pool below the skimmer while the pump is still connected will cause the pump to suck in air. The dry motor will then overheat, resulting in costly repairs and possibly requiring replacement.

Safely Draining a Pool with Skimmers

So what happens when you need to drain your pool below the skimmer? Is there an alternative path you can take?

Fortunately, there are safety precautions that can help you prevent damage to your pool pump and motor when draining a pool below the skimmer, and they are listed below:

  • Open your main drain valve fully (usually found at the deepest part of your pool), then close the skimmer’s valve to prevent it from sucking air while maintaining the pool’s water circulation system.
  • If your pool has a diverter valve, redirect it from the skimmer to the main drain valve.
  • Connect a 1.5-inch (3.8 centimeters) backwash hose to the multiport valve, and adjust the waste setting to allow water to flow out. 
  • Let the pump run to drain the pool until the water level is at most six inches (15.24 cm) below the skimmer, then switch it off so that it doesn’t dry out and cause the motor to overheat.
  • Consider using a submersible pump to drain the pool rather than the pump since it is safer.

This process requires you to be familiar with your pool’s plumbing system. This video gives a detailed guide that will help you identify the various pipes and operate the valves as needed:

Other Things You Should Know About Draining a Pool

Due to the risks involved, draining a pool is an intricate process that often requires particular expertise. Professionals recommend that you avoid draining your pool unless it is for the following necessary reasons:

So, what risks are associated with incorrectly draining a pool? Here is what you should know:

  • Concrete pools tend to crack when the pool is drained during hot weather, resulting in pool water sipping into the ground.
  • Groundwater exerts hydrostatic pressure on inground pools, balanced out by filling the pool with water. Improperly draining the pool can cause damage to the pool walls due to excess hydrostatic pressure. 
  • Vinyl and fiberglass pool walls are prone to collapsing or bulging walls because of their structure, which is insufficient to withstand external pressure exerted on pool walls (which is otherwise balanced out by water pressure when the pool is filled).
  • Fiberglass pools can ‘pop’ out of the ground when drained. This is because the water pressure in the pool is necessary to hold the fiberglass shell in place.
  • Due to clogged or damaged pipes, sewer water backs into the pool. 
  • Damaging the filter pump because of drying it out while draining the pool.

These risks may cause irreversible damage to your pool; therefore, you need to consult an expert who will guide you on the best alternatives to draining your pool. In most cases, it should only be the last resort.

Valuable Pool Care Tips When Draining Your Pool

Follow these pool care tips when draining your pool to mitigate risks and prevent expensive repairs and replacements:

  • Switch off automatic timers to prevent water-cooled parts, such as the pool pump and lights, from turning on and overheating as the pool drains.
  • Avoid draining the pool when it is too hot out, as the pool liner can succumb to high heat (above 85 °F or 29 °C).
  • Dechlorinate your pool water before draining, as the chlorine may harm aquatic life, plants, and trees.
  • Have a professional on call because their expertise and experience are invaluable.

In addition to these tips, it would be beneficial for you to research local regulations regarding draining pool water, as some areas do not permit draining into sewers and storm drains. Doing this will save you in fines and penalties.

Water Leveling Wide mouth Above Ground Skimmer. pool water filtration system

Final Thoughts

There are several factors you should consider before draining your pool, like keeping a safe distance between the water level and the pool skimmers. The recommended maximum distance you should maintain is 6 in (15.24 cm) from the bottom of the skimmer to keep the pool pump from drying out and overheating.

As a pool owner, you should also familiarize yourself with other risks associated with draining your pool to mitigate them and prevent costly repairs and replacements.

One point to remember is to always consult a professional before making any significant adjustments to your pool, such as draining.

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