How Do I Backwash a Pool Filter?

Turn off the pump, set the filter to 'backwash,' restart the pump, and run until the water in the sight glass runs clear.

What Is Backwashing?

Backwashing is the process of reversing the water flow in your pool filter to remove trapped debris. It’s necessary when your filter pressure rises or water flow decreases.

How Often Should I Backwash My Pool Filter?

You should backwash your pool filter when the pressure gauge reads 8-10 psi above normal levels or at least once every 1-2 weeks during peak season.

Steps to Backwash a Pool Filter

Follow these steps to backwash your filter properly:

1. Turn Off the Pool Pump

• Always shut off the pool pump before changing filter settings.

• Running the pump during backwashing can damage the system.

2. Set the Filter Valve to "Backwash"

• On a multiport valve, turn the handle to the Backwash setting.

• For push-pull valves, open the valve by pulling it upward.

3. Connect a Backwash Hose

• Attach a backwash hose to the waste port to direct dirty water away from your pool area.

• Ensure the hose is securely attached to avoid leaks.

4. Turn the Pump On

• Switch the pump on and run it for 2-3 minutes or until the water runs clear in the sight glass.

• Watch the discharge water to know when the backwash process is complete.

5. Rinse the Filter

• Turn the valve to the Rinse setting and run the pump for 30-60 seconds.

• This step helps resettle the sand or DE powder inside the filter.

6. Return to Normal Operation

• Set the valve back to Filter mode.

• Turn on the pump and check that the pressure returns to normal levels.

Additional Tips for Effective Backwashing

• Avoid excessive backwashing; it can waste water and reduce filter efficiency.

• If your pool is heavily used or surrounded by trees, you may need to backwash more frequently.

• Clean your skimmer and pump baskets regularly to reduce strain on your filter.

Types of Pool Filters and Backwashing Methods

Each filter type has unique backwashing needs:

• Sand Filters: Requires backwashing about every 1-2 weeks or after heavy use.

• Diatomaceous Earth (DE) Filters: Needs backwashing and recharging with fresh DE powder after each backwash.

• Cartridge Filters: These cannot be backwashed; instead, remove the cartridge and clean it manually.

How to Know When Your Pool Filter Needs Backwashing

Look for these signs that indicate it's time to backwash:

1. Increased Pressure: Check your pressure gauge, if it's 8-10 psi above normal, it’s time to backwash.

2. Cloudy Water: Poor water clarity often signals a clogged filter.

3. Weak Water Flow: Reduced return jet pressure can mean the filter needs cleaning.

Preventive Maintenance for Your Pool Filter

• Clean your filter thoroughly at the start and end of the pool season.

• Regularly inspect the filter’s O-rings and gaskets for signs of wear.

• Consider using a filter cleaner to break down stubborn oils and debris.

By backwashing your pool filter regularly, you’ll improve water circulation, extend your filter’s lifespan, and enjoy cleaner pool water all season long.