How to Backwash a Pool Filter

A Step-by-Step Guide for Central Florida Homeowners

Backwashing your pool filter is an essential part of keeping your water clean and your equipment running efficiently. In Florida’s warm climate—where pools run nearly year-round—filters collect dirt, sand, pollen, and debris more quickly than in other regions. Knowing how to properly backwash your system ensures strong circulation, better water clarity, and longer filter life.

At Professional Pool Company, we teach homeowners simple methods to safely and effectively maintain their filtration systems.

⭐ What Is Backwashing?

Backwashing is the process of reversing the flow of water through your filter to flush out trapped dirt and debris.

It applies to:

• Sand filters
• DE (Diatomaceous Earth) filters

Cartridge filters do not get backwashed and require manual cleaning instead.

When your pressure gauge reads 8–10 psi above the clean starting pressure, it’s time to backwash.

⭐ How to Backwash a Pool Filter (Step-by-Step)

✔ 1. Turn Off the Pool Pump

Always shut off power before changing filter settings.

Running the pump with the valve in the wrong position can damage equipment.

✔ 2. Set the Multiport Valve to “Backwash”

Most filters have a multiport valve with options like:

• Filter
• Backwash
• Rinse
• Waste
• Recirculate

Move the handle to Backwash and ensure it locks into place.

✔ 3. Attach or Direct the Backwash Hose

Make sure the hose is:

• Laid flat
• Pointed downhill
• Draining into an approved area

Backwash water should never be discharged into storm drains.

✔ 4. Turn the Pump Back On

Let it run 2–3 minutes or until the sight glass shows clear water.

You’ll see:

• Dirty water → cloudy water → clean water

Once clear, turn the pump off again.

✔ 5. Set Valve to “Rinse”

This step settles the sand or DE inside the filter.

Run the pump on Rinse for 20–30 seconds.

Turn the pump off again.

✔ 6. Return Valve to “Filter”

This returns your system to normal circulation mode.

✔ 7. Turn the Pump Back On and Check Pressure

The pressure should drop back to the normal “clean filter” reading.

If not, you may need a second backwash—or the filter media may be worn out.

⭐ How Often Should You Backwash?

In Central Florida, we recommend backwashing:

• Every 3–6 weeks for sand filters
• Every 4–6 weeks for DE filters
• After major storms or heavy debris loads
• Whenever pressure rises 8–10 psi above normal

During pollen season, extra backwashing may be necessary.

⭐ Tips for Sand and DE Filters

Sand Filters

• Replace sand every 5–7 years
• Use filter cleaner once or twice a year
• Backwash only when needed—over-backwashing reduces efficiency

DE Filters

• Re-add DE powder after backwashing (usually 1 lb per 10 sq ft of filter area)
• Take the filter apart for a deep cleaning once per year

⭐ Common Backwashing Mistakes to Avoid

🚫 Backwashing too often – reduces filtration quality

🚫 Forgetting to rinse – sends dirty water straight back into the pool

🚫 Running the pump dry – can damage seals and motor

🚫 Ignoring rising pressure – strains the pump system

🚫 Not re-adding DE powder (for DE filters) – eliminates filtration ability

⭐ ProPoolCo Recommendations

To keep your pool clear and equipment healthy:

• Monitor your pressure gauge weekly
• Backwash only when needed
• Clean filters after storms or heavy debris
• Schedule annual filter maintenance

Good filtration is the backbone of clean, healthy pool water.

⭐ Need Filter Help?

Professional Pool Company provides troubleshooting and expert maintenance for pool filtration systems across Central Florida.

👉 Call 321-252-7371 or visit propoolco.com for support.

Updated on: 05/12/2025