Pool Draining 101

We hate the thought of an empty swimming pool. We prefer seeing full, healthy, safe pools being enjoyed as often as possible. Sometimes, however, draining a pool is necessary. As your trusted pool care partner, we want to make sure you know when draining your pool is the right call — and how to execute it properly.

Reasons to drain your pool

Leslie's Water Balancing
Poor water quality, due to an overabundance of Total Dissolved Solids or high levels of Cyanuric Acid, is the most common reason for needing to drain a pool.

Leslie's Calendar
Even with proper and regular pool maintenance, it's often necessary to drain your pool — completely or partially — every 3-5 years.

Draining your pool often isn't necessary, especially if you're following a proper and regular pool maintenance program. There are a few reasons, however, that would lead to needing to completely — or partially — drain your pool.

The most common reason for needing to drain your pool is an overabundance of Total Dissolved Solids (TDS). Over time, TDS slowly increase in your pool water, and once you reach about 2500 ppm, you start to lose the ability to balance the water. Your first response is likely to add more chemicals, but that will not solve the problem. Depending on the quality of your fill water and the quality of chemicals you typically add, you should expect to drain your pool every 3 to 5 years due to TDS.

Another reason for draining — or partially draining — your pool is high Cyanuric Acid (CyA) levels. CyA builds up in the water and cannot be removed by the addition of chemicals, so the most economical way to reduce CyA is to partially drain and add fresh water to your pool, which dilutes the remaining CyA in the water.

You might also need to drain your pool to do certain types of repair work or to resurface and repaint.

Before you drain your pool

  • Check with your local municipality to find out when and where it is suitable to drain your pool water. Most towns and cities have ordinances against discharging water into storm drains.
  • Consider the groundwater levels in your area. High groundwater levels can cause an empty in-ground pool to pop out of the ground. If high groundwater is present in your area, it is best to only partially drain your pool.
  • Never completely drain a fiberglass or in-ground vinyl liner pool; doing so can damage the integrity of the pool surface or liner in the form of bowing or cracking. The best practice is to partially drain these types of pools and always complete partial drains by 1/3 of the water at a time.
  • Remove the trippers from your pump and pool light prior to draining.

DIY TIP: If possible, drain the pool when the outside air temperature is less than 85 °F. Spring is generally an ideal time to drain your pool.

How to drain your pool

There are a few things to keep in mind in order to drain your pool safely. Never use your pool pump to try to drain the pool. Inevitably, you will pull air into your suction line, the pump will lose its prime, and you will damage or burn up your pump. Always rent or purchase a submersible pump to drain the pool. Remember to turn off the electricity to your pump and pool light.

After draining the old water, you can refill the pool with a garden hose. The usual amount of time to entirely refill a pool is 14-16 hours with two hoses.

DIY TIP: To fill the pool quicker, use two hoses if you have them available.

Test your water immediately after refilling to balance and
add start-up chemicals. You can also take a water sample into a Leslie’s store for testing. Leslie’s
will test your water and provide the results with a prescription for improving
your water quality.

Not sure if your pool needs draining or have other questions? Visit your local Leslie’s store or call 1-800-LESLIES to ask an expert. We are here to help you every step of the way.