Pool Closing Guide

At Leslie’s, we understand the importance of proper pool maintenance, even during the off-season. From water balance to freeze protection, we're here to help. In this post, we’ll discuss the steps to prepare your pool for closing, and we'll also talk about how to properly winterize your pool to protect it from freezing temperatures.

Remember to not close your pool too early. Pool water needs to be consistently below 65 degrees before closing for the winter. Closing too soon can cause the sanitizer to be used up too quickly, which can increase the risk of algae growth. This may cause more work, extra hassle, and additional expense when opening the pool back up in the spring.

CLICK HERE to download Leslie's FREE Pool Closing Checklist

Pool Closing & Winterizing Checklist

To make things easier, we’ve put together a quick checklist with the proper steps on how to winterize a pool.

STEP 1: Clean and Balance

  • Brush, rake, and vacuum the pool to remove dirt and leaves. Don’t leave anything behind for bacteria or algae to eat.
  • Make sure your water balance is in the normal range:
    • Available Chlorine: 2.0 – 4.0 ppm
    • Total Alkalinity: 80 – 120 ppm
    • pH: 7.4 – 7.6 ppm
    • Water Hardness: 200 – 400 ppm
    • Cyanuric Acid (CYA): 30 – 100 ppm
  • Let your pool pump complete one cycle, then backwash the filter.
  • Using a submersible pump, lower the water 4-6 inches below the skimmer inlet or tile line, whichever is lower.

STEP 2: Winterize

  • Drain the filtration system entirely.
  • Turn off the main power supply and remove the “on” and “off” trippers on your time clock, if you have one.
  • Position your multiport valve handle between any two settings, or the winter setting if you have one.
  • If you have an above ground pool, disconnect the filter hoses from the skimmer and pool return fittings.
  • Blow out the pool lines to remove water from the plumbing. Once all the water is out of your filtration system, insert winterizing plugs into return and skimmer lines so water doesn’t get back in.
  • Adding swimming pool anti-freeze to the pool lines can help prevent expansion caused by freezing. Some pool owners also add a gizzmo to absorb freezing water from damaging the skimmer lines after pool closing.
  • In moderate freezing climates where the equipment stays connected through the winter, we recommend adding a freeze protector to prevent frozen plumbing. A freeze protector will trigger water circulation at low temperatures.

STEP 3: Prepare Deck or Surrounding Area

  • Remove all ladders, hoses, pool cleaners, and over-the-top skimmers. Lay any hoses out straight in a non-freezing location.
  • Make sure to drain all of the water out of your automatic pool cleaner.
  • For above ground pools, inflate the air pillow and tie to an anchor with rope. As an alternative, you can use the Pillow Pal to attach the air pillow to the bottom of your winter cover.
  • Attach a floating chlorinator to your air pillows and set to the lowest possible feed. This is essential for plaster pools.

STEP 4: Size Your Pool Cover

  • Take measurements of your pool and write them down prior to pool closing.
  • Leslie’s sizes its standard winter covers assuming the water level is approximately 18” below the deck. If your water line is below 18” or an air pillow is being used, add 2’ to the measurement, as a larger cover will be needed.

STEP 5: Cover Your Pool

  • Carefully unfold the cover and pull it across the pool.
  • Ensure the winter cover is centered.
  • For above ground pools, run a cable through all of the grommets and tighten until snug. Some pool owners also attach water bags to help weigh down the cover.
  • For inground pools, use the grommets to secure the water bags, water tubes, or water blocks. Make sure to follow the manufacturer instructions for best results in sealing your pool with the winter cover.
  • Place a water siphon or pool cover pump on the cover to drain rainwater, melted snow or other precipitation from the cover. You may also opt to use a small submersible pump.
  • We recommend checking the chemical balance about once a month after pool closing, and remember to remove all excess water and debris from the cover.