What Is a Pool Skimmer and How Does It Work?

What is a pool skimmer? It is the part of a pool’s circulation system that pulls water from the surface, catches floating leaves, bugs, and debris in a basket, and sends the water on to the pump and filter. On most inground pools and many above-ground pools, it is the rectangular opening in the wall at the waterline with a round lid on the deck above it. The word also covers hand-held skimmer nets and floating robotic skimmers, which do the same job in different ways. This guide explains each type, how a built-in skimmer works, and how to keep its basket clean.

What Is a Pool Skimmer and What Does It Do?

Most debris lands on the surface first. Leaves, grass clippings, pollen, and insects float for a while before they get waterlogged and sink. A skimmer’s job is to catch them during that window, when they are easy to remove and have not yet started to stain the floor or feed algae.

Hayward’s owner’s manual for its Dyna-Skim thru-wall skimmer describes the process in one line: leaves, insects, and floating debris are pulled from the pool into the skimmer basket. Intex describes its Deluxe Wall Mount Surface Skimmer the same way, as a unit that routes surface water through the strainer basket on its way to the filter pump, catching leaves and debris before they sink to the bottom of the pool.

A skimmer does not clean the floor or walls. Debris that has already sunk needs a vacuum or a pool cleaner. Think of the skimmer as the first line of defense and the cleaner as the second.

How a Built-In Pool Skimmer Works

A built-in skimmer is connected to the suction side of the pool pump. When the pump runs, it draws water into the skimmer opening, through the basket, and down the pipe to the pump and filter. The main parts are:

• Mouth (throat): The opening in the pool wall at the waterline where surface water enters.
• Weir: A hinged flap across the mouth. Hayward’s Dyna-Skim product page explains that the weir floats into an upright position as the water level in the pool rises. The flap lets a thin layer of surface water spill in and helps keep debris from floating back out when the pump cycles off.
• Basket: A removable plastic basket inside the skimmer body that traps leaves and larger debris before they reach the pump.
• Lid: The cover on the deck (on inground pools) or on top of the skimmer housing (on above-ground pools) that gives you access to the basket.
• Suction port: The outlet at the bottom of the skimmer that connects to the pump line. Some skimmers let you attach a vacuum hose here.

Because the skimmer only draws from the surface, water level matters. If the water drops below the mouth, the skimmer can pull in air instead of water, which starves the pump. If the water sits too high, the weir cannot do its job and surface debris passes by. Keep the level within the range shown in your skimmer or pool manual.

Types of Pool Skimmers

Built-in skimmers for inground pools

These are set into the pool wall when the pool is built and plumbed to the pump under the deck. You service them through the deck lid. They run whenever the pump runs, so they do most of the daily surface cleaning on an inground pool. Replacing one usually means cutting into the deck or wall, which is a job for a pool contractor.

Thru-wall skimmers for hard-sided above-ground pools

Steel-wall and resin above-ground pools use a skimmer that bolts through a cutout in the wall and connects to the filter by hose or pipe. Hayward says its Dyna-Skim skimmers were redesigned to match the needs of today’s above-ground pools, and its manual covers installation on vinyl-lined walls. These work like inground skimmers, with a weir, a basket, and a top lid.

Wall-mount skimmers for soft-sided pools

Inflatable and frame pools usually have no skimmer opening. A wall-mount unit hangs on the pool wall and connects to the filter pump hose instead. Intex says its wall-mount skimmer mounts to Easy Set or Metal Frame pool sidewalls and requires an Intex filter pump with a minimum flow rate of 800 gallons per hour. Check your pump’s rated flow against that requirement before buying an add-on skimmer.

Hand skimmer nets

A skimmer net is a flat or bag-style net on a telescoping pole. It needs no power and works on any pool. A flat net is easier for scooping bugs and small leaves off the surface; a deep bag net holds more, which helps when you are pulling a load of leaves off the water or the floor. Even pools with a good built-in skimmer need one for corners, steps, and debris the skimmer misses.

Robotic and solar surface skimmers

A robotic pool skimmer is a floating, battery-powered unit, often charged by a solar panel on top, that moves around the surface and collects debris in its own basket. It does not connect to your pump, so it keeps skimming when the pump is off. It still has a basket that needs emptying, and its runtime depends on the battery, sunlight, and the maker’s design. Read the manual for charging, cleaning, and storage directions.

Which Skimmer Setup Fits Your Pool

• Inground pool with a few trees nearby: The built-in skimmer plus a hand net usually covers it. Empty the basket often during leaf season.
• Inground pool under heavy tree cover: Consider adding a robotic surface skimmer so debris is caught between pump cycles, along with a leaf net for big drops.
• Hard-sided above-ground pool: A thru-wall skimmer matched to your wall type and filter, plus a hand net.
• 15 ft frame or inflatable pool: A hand net is the minimum. A wall-mount skimmer helps if your filter pump meets the skimmer’s flow requirement; a solar robotic skimmer is the other option if it does not.

Who should skip a robotic skimmer? If your pool is small, mostly sunny, and gets little debris, a net and the built-in skimmer are enough. If you are choosing a pool skimmer for a yard with little sun, a robotic skimmer that depends on solar charging may struggle; check whether the model can also charge by cable. You can browse skimmer gear and other add-ons in the pool accessories section.

How to Clean a Pool Skimmer Basket

Hayward’s skimmer manuals, including the one for its front access skimmer, give a short procedure: remove the top cover, or fold the weir forward and squeeze its pins toward the center to remove it, then remove and clean the basket. The same manuals warn that, before servicing the pool’s water circulation system, all system and pump controls must be in the off position. Put together, a routine basket cleaning looks like this:

1. Turn the pump off at its control or timer, as the manual directs, so nothing is being pulled through the skimmer.
2. Open the skimmer. Lift the deck lid on an inground pool or the top cover on an above-ground skimmer. If your model is serviced from the front, remove the weir as the manual describes.
3. Lift out the basket by its handle. Hold it level so debris does not spill back into the skimmer.
4. Empty it into a trash bag or yard waste bin. Knock out stuck leaves; a quick rinse with a garden hose clears fine debris.
5. Inspect it. A cracked or broken basket lets leaves through to the pump strainer. Replace it with the part listed in your skimmer’s manual.
6. Reinstall and restart. Seat the basket fully, replace the weir and lid, then restart the pump following the manual’s startup steps.

How often? Hayward’s manual simply says to clean the basket regularly. In practice, empty it before it fills up, which can mean daily during heavy leaf or pollen seasons. A packed basket cuts flow to the pump and filter. Hayward’s manual also warns that failing to keep suction outlet components clear of debris such as leaves, dirt, hair, and paper can increase the potential for suction entrapment, so a clean skimmer is a safety habit as well as a maintenance one.

Other Skimmer Maintenance

• Check the weir. It should move freely. A stuck or missing weir lets debris float back out of the skimmer.
• Watch for leaks. Hayward notes that ongoing leaks from the skimmer or wall fittings may cause pool wall damage. Water stains or soft ground under an above-ground skimmer are a sign to call for service.
• Vacuum through the skimmer if your model allows it. Hayward describes a Skim-Vac accessory that sits over the basket so you can vacuum through it, which keeps debris out of the pump.
• Winterize by the manual. For its Dyna-Skim above-ground skimmer, Hayward’s winterizing procedure says to drain the pool to approximately 6 inches below the skimmer opening and keep the skimmer free of water accumulation, and notes that the warranty does not include damage caused by ice in the skimmer.

When to Call a Pro

Call a pool service company if the skimmer body is cracked, water is leaking around the skimmer throat, or the pump keeps losing prime even with a clean basket and a correct water level. On inground pools, skimmer replacement involves the deck, the wall, and buried plumbing. Any work on the pump’s electrical supply belongs to a licensed electrician.

FAQ

Where is the skimmer on a pool?

On an inground pool, look for a rectangular opening in the wall at the waterline, with a round lid on the deck right above it. On a hard-sided above-ground pool, it is a box mounted on the wall near the top, usually close to the filter.

Does the pump need to be off to empty the skimmer basket?

Yes. Hayward’s skimmer manuals state that all system and pump controls must be off before servicing the circulation system. Turn the pump off, empty the basket, then restart.

Do above-ground pools have skimmers?

Most hard-sided above-ground pools have a thru-wall skimmer. Many inflatable and frame pools do not, but you can add a wall-mount skimmer if your filter pump has enough flow, or use a hand net or robotic surface skimmer.

Is a robotic skimmer the same as a robotic pool cleaner?

No. A robotic skimmer stays on the surface and collects floating debris. A robotic pool cleaner works underwater on the floor and walls. Many pools with heavy debris benefit from both.

Why is my skimmer not pulling water?

The usual causes are a full basket, a water level below the mouth, a stuck weir, or a clogged pump strainer basket. Check those first. If flow is still weak, have a pool service check the plumbing for leaks or blockages.

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