how do you backwash a pool filter


Author: Poolking - Swimming Pool Equipment Manufacturer

Backwashing a pool filter is a crucial maintenance step that helps keep your pool clean and efficient. When you backwash your pool filter, you are essentially reversing the flow of water through the filter, flushing out all the debris and contaminants that have been trapped inside. Knowing how to backwash a pool filter is a must-have skill for any pool owner. In this article, we will guide you through the process of how to backwash a pool filter step by step.

Why Should You Backwash Your Pool Filter?

Before we start, let's take a moment to understand why pool filter backwashing is so important. Over time, your pool filter can become clogged with dirt, debris, and other contaminants. When this happens, the filter becomes less effective at removing impurities from the water. In some cases, a clogged filter can even damage the pool pump or cause other issues. By backwashing your pool filter regularly, you can ensure that it is functioning properly and keep your pool water clean and clear.

When Should You Backwash Your Pool Filter?

Most pool experts recommend backwashing your pool filter once every four to six weeks, or as needed. However, the frequency of backwashing will depend on several factors, such as the size of your pool, the type of filter you have, and how often you use your pool. In general, if you notice that the water flow from your pool's return jets is weak or if the water looks cloudy, it's time to backwash your pool filter.

Steps for Backwashing Your Pool Filter

Now that we've covered the importance of backwashing your pool filter let's get into the nitty-gritty of the process. Here's how to backwash a pool filter step-by-step:

Step 1: Turn off Your Pool Pump

The first step is to turn off your pool pump. This will prevent any water from flowing through the filter during the backwash process.

Step 2: Locate Your Pool Filter's Backwash Valve

The backwash valve is usually located near the filter or on top of the multiport valve, depending on the type of filter you have. Consult your pool manufacturer's instructions to locate the valve.

Step 3: Connect the Backwash Hose

The backwash hose is a special hose that attaches to the backwash valve and redirects water away from the filter. Connect the hose to the valve and secure it in place.

Step 4: Adjust the Filter Valve to Backwash Mode

If your pool filter has a multiport valve, you'll need to turn it to the backwash mode. This will allow water to flow out of the backwash valve and through the hose.

Step 5: Turn on the Pool Pump

Turn on the pool pump, and water will flow out of the backwash valve and through the hose. Watch the water in the sight glass or through the backwash hose. You'll notice it starts off cloudy and gradually gets clearer.

Step 6: Monitor the Process

Backwashing typically takes about 2-3 minutes, but this can vary depending on the filter size and the amount of debris in the filter. Once the water flowing out of the hose becomes clear, you can turn off the pump.

Step 7: Rinse the Filter

Some pool filters require rinsing after backwashing. This helps flush out any remaining debris before the filter goes back to its normal filtration mode. To rinse the filter, turn the valve to the rinse mode, turn on the pump for 30 seconds or so, and then turn it back to the filter mode.


Keeping your pool filter in good working condition is essential for maintaining your pool water's cleanliness and clarity. Backwashing is a simple process that can help prevent clogs and ensure that your filter is working at optimum capacity. With the steps provided here, you'll be able to backwash your pool filter like a pro in no time. Just follow the guidelines, and you'll get clear and sparkling pool water every time.


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