Pool Pump Suction vs Pressure Side: Which Do You Need?

What a suction-side pump does

A suction-side pool pump is the main pump on most residential pools. It creates suction at the skimmer and main drain, pulling water through the pump's strainer basket, then pushing it under pressure through the filter and back to the pool via return jets. This is the pump that circulates and filters the water.

In a listing, a suction-side pump is usually just called a "pool pump" or "filter pump." It may be described as self-priming, which means it can pull water from the pool even when the pump is above water level. Most inground pumps are self-priming; above ground pumps often sit below the waterline and do not need to be self-priming.

The pump's horsepower and flow rate determine how much water it moves. For example, a pump with a higher stated horsepower can move more gallons per minute (GPM), but the actual flow depends on the plumbing, filter, and pool size. This site does not size pumps to pools; use the maker's sizing page and an installer's advice. For more on horsepower, see pool pump horsepower explained.

What a pressure-side pump does

A pressure-side pump is an additional pump that connects to the return line, after the filter. It boosts water pressure to power a pressure-side pool cleaner, which moves around the pool collecting debris into its own bag. This pump is often called a "booster pump."

Pressure-side pumps are not used for filtration; they only provide extra flow to the cleaner. They are typically installed in addition to the main suction-side pump. Some listings for pressure-side cleaners include the booster pump, while others sell the cleaner separately.

If you see a pump listing that says "booster pump" or "pressure cleaner pump," it is for this purpose. It will have its own horsepower rating and may be labeled for use with specific cleaner models. The pump and cleaner must match in flow requirements, so check the maker's specifications. Learn about flow rate in pool pump flow rate GPM.

Which one does your pool need?

Every pool needs a suction-side pump for circulation and filtration. Without it, water does not move through the filter, and the pool cannot stay clean. This is the pump you will run daily, often on a timer.

A pressure-side booster pump is optional. You only need one if you plan to use a pressure-side cleaner. If you choose a robotic cleaner, which runs on low-voltage electricity and does not use the pool pump, you do not need a booster pump. If you choose a suction-side cleaner, it attaches to the skimmer or dedicated suction line and runs off the main pump, so no booster is needed.

Consider your pool's plumbing. A pressure-side cleaner requires a dedicated return line or a connection at the return jet. If your pool does not have that, a suction-side cleaner or a robotic cleaner may be simpler. Ask your installer about your pool's configuration. See pool cleaner type robotic suction pressure for a comparison.

Reading pump listings for suction or pressure

When shopping, read the listing title carefully. A title that says "pool pump" or "filter pump" usually refers to the suction-side main pump. A title that says "booster pump" or "pressure pump" indicates a pressure-side pump.

Some listings may say "for inground pools" or "for above ground pools." This tells you the intended pool type, not the suction or pressure side. A booster pump is typically for inground pools, but check the listing.

The horsepower figure is stated by the seller. For a main pump, horsepower ranges from about 0.5 to 3 HP. For a booster pump, it is often 1 to 2 HP. This site does not match horsepower to pool size; use the maker's sizing page. For more on horsepower, see pool pump horsepower vs THP.

Matching the pump to your cleaner

If you already own a pressure-side cleaner, you need a booster pump that meets its flow requirements. The cleaner's listing will state a minimum flow rate in GPM. The booster pump's listing will state its flow output. Match these numbers, but verify with the maker's manual.

If you are buying a new cleaner, decide first whether you want a robotic, suction-side, or pressure-side model. Robotic cleaners are independent of the pump. Suction-side cleaners use the main pump's suction. Pressure-side cleaners need the booster pump.

This site cannot say which cleaner type cleans better. The choice depends on your pool's surface, debris load, and plumbing. Read the cleaner listings for stated features like wall climbing and cordless operation, and compare stated details. See pool cleaner pump connection for more.

Questions to ask before buying

Before you buy a pump, ask an installer or the maker's support these questions: Does your pool have a dedicated suction line for a cleaner? Is there a return line for a pressure-side cleaner? What flow rate does your filter require? What horsepower does your pool need?

For electrical questions, such as voltage or wiring, a licensed electrician and the maker's manual decide. For gas or fuel questions, a licensed gas installer and the maker's manual decide. This site does not advise on wiring or gas lines.

Check with your local building office about any permits or codes. The Pool & Hot Tub Alliance (PHTA) publishes standards for pool construction and equipment, but local codes vary. Ask your installer about compliance. For more on pump selection, see best inground pool pumps and best above ground pool pumps.

What to pick for your situation

Questions

Can you use a pressure-side pump as your main pump?

No. A pressure-side booster pump is designed to power a cleaner, not to circulate and filter the pool. You still need a suction-side main pump for filtration.

Do you need a booster pump for a suction-side cleaner?

No. A suction-side cleaner attaches to the skimmer or a dedicated suction line and runs off the main pump's suction. It does not require a separate booster pump.

What is the difference between a suction-side and pressure-side cleaner?

A suction-side cleaner connects to the pool's suction line and uses the main pump's suction to move and collect debris. A pressure-side cleaner connects to the return line and uses a booster pump's pressure to move and collect debris into its own bag.

How do you know if your pool has a dedicated suction line?

Check the pool's plumbing at the equipment pad. A dedicated suction line has a separate pipe from the pool to the pump, often with a valve. If unsure, ask an installer to inspect the plumbing.

Can a robotic cleaner replace your pool pump?

No. A robotic cleaner cleans the pool but does not circulate or filter the water. You still need the main pump for filtration and water circulation.