How to Winterize Your Pool in 9 Simple Steps

Winterizing your pool properly ensures it remains in excellent condition throughout the offseason and helps you get a head start on pool opening when the weather warms up. With a few basic steps and the right tools, you can safely and effectively close your pool for the winter. Here's how to do it, whether you have an inground or above-ground pool.

When Should You Winterize Your Pool?

For the best results, you should start winterizing your pool when the outside temperature consistently drops below 65°F (18°C). Colder temperatures help prevent algae growth and keep the water clearer through the winter months. However, if you experience occasional warm days, you can continue monitoring your water chemistry until it’s time to fully close the pool.

Supplies You’ll Need to Winterize Your Pool

Before you begin winterizing your pool, make sure you have the right supplies. These include:

• Pool cover (winter or safety cover)
• Water tubes (for pools without an inground safety cover)
• Rubber plugs to block water from entering plumbing
• Skimmer protector (such as a Gizzmo or skimmer plate)
• Air pillow (for above-ground pools)
• Air compressor (for inground pools, if you plan to blow out the lines)
• Wet/dry vacuum to remove standing water
• Submersible pump to lower water levels
• Pool chemicals: pH increaser/decreaser, alkalinity increaser, polyquat 60% algaecide, chlorine shock, metal sequestrant

Having everything on hand will save you time and hassle as you winterize your pool.

Step 1: Clean Your Pool

Start by scrubbing the walls and floor of your pool to remove any dirt, algae, or debris. Use a pool brush attached to a telescoping pole to scrub hard-to-reach spots. Vacuum the pool to remove any loosened debris. If there’s visible algae, make sure to treat it before closing the pool to prevent it from causing problems later.

Step 2: Test the Water and Balance the Chemistry

Before closing your pool, ensure the water chemistry is properly balanced. This prevents potential corrosion or scaling over the winter months. Use a pool test kit to check the following levels:

• pH: 7.2 to 7.8
• Alkalinity: 80 to 120 ppm
• Chlorine: 1 to 3 ppm

Ensure the chlorine level is not too high (above 5 ppm), as this can interfere with winterizing chemicals. Adjust the pH and alkalinity as needed.

Step 3: Shock Your Pool

Shocking your pool with chlorine helps eliminate any remaining bacteria, algae, and contaminants. It’s best to shock the pool a day or two before closing it to ensure it has time to circulate. Always add shock at night when the sun is not strong, as the sun can break down chlorine before it has a chance to work effectively.

Step 4: Add Winterizing Chemicals

To keep your pool in good condition during the winter months, add the following winterizing chemicals:

• Polyquat 60% algaecide: Prevents algae growth during the offseason. If you have a mesh cover that allows debris in, consider using a double dose.
• Metal sequestrant: If your water has high metal content (from well water, for example), this will help prevent staining on your pool surfaces.

You can also add a winter pill or pool enzymes, which help maintain clear water by breaking down organic material and reducing the load on your algaecide.

Step 5: Clean and Backwash the Filter

A clean filter is essential for pool maintenance. Remove and clean your pool filter thoroughly before closing the pool. For sand filters, backwash the filter to remove debris. For DE filters, follow the manufacturer’s instructions to ensure they are properly cleaned. If you have a pool heater, drain it along with the pump and filter to prevent any damage.

Step 6: Lower the Water Level (Optional)

This step is optional but recommended to prevent freezing issues, especially in cold climates. Lower the water level 3–4 inches below the skimmer to protect the skimmer and plumbing. You can skip this step if you have a winter cover plate for the skimmer, which keeps the skimmer protected from freezing water.

Step 7: Blow Out the Plumbing Lines (Inground Pools Only)

For inground pools, it's crucial to blow out the water from your plumbing lines to prevent freezing and cracking. You’ll need an air compressor to do this. The process involves blowing air through the return lines, skimmers, and drains to ensure no water is left in the system. This will prevent ice from forming and damaging the plumbing. If you're unsure about the process, it's a good idea to hire a professional to help.

Alternatively, you can use pool antifreeze in the lines if blowing out the system is not an option in your area.

Step 8: Remove Pool Accessories

Take out all pool accessories, such as ladders, rails, and automatic cleaners. Leaving them in place exposes them to harsh winter conditions, which can cause rust or damage. Clean and dry all accessories before storing them in a dry, cool place.

Step 9: Install a Pool Winter Cover

Finally, cover your pool with a durable winter cover. Choose between a standard winter cover or a safety cover, depending on your pool type and budget. A safety cover is more expensive but provides added protection against debris, animals, and accidental falls. Be sure to use water bags or cover clips to secure the cover in place and prevent gaps where debris or water could enter.

For safety, use a pool cover pump to remove any accumulated water. Regularly check the cover for leaves, snow, or water buildup to ensure it remains effective throughout the winter.

Hire a Professional When Needed

While winterizing your pool is a straightforward process, certain steps—like blowing out the plumbing lines—can be tricky, especially if you’re unfamiliar with the procedure. If you're not confident in handling these tasks, it’s perfectly fine to hire a pool professional to ensure your pool is properly winterized.

Taking the time to close your pool properly will protect your investment and make the spring opening much easier. With AQUASTRONG's pool products and resources, you can rest assured your pool will be ready for the next swimming season.