The Parts of a Swimming Pool: What They Each Do (Diagram)

in-ground swimming pool

The Spruce / Letícia Almeida 

How intimately do you know the parts of your swimming pool? If you maintain it yourself—even part-time—then you should know about some of the inner workings of that big body of water in your yard. Let us help you take the mystery out of some of the main components of your swimming pool equipment, so at least if the pool repair person is explaining something, you won't have a spacey, far-off look in your eyes as he/she uses terms like surface skimmer and filtration system.

The Parts of a Swimming Pool

The Spruce / Xiaojie Liu

What Is Backwashing?

First, you may have heard of the term backwashing. You can't go to a pool supply store and ask to buy a backwasher. They might know what you're talking about, but you'll give away that you don't know the correct terms for the parts of your pool. Whether you buy your pool equipment from a local retailer or shop online, this is an important word to know for general pool maintenance.

So exactly what does backwashing mean, and what does it have to do with a swimming pool? Very simply, the backwashing process reverses the flow of water to flush out contaminants from a swimming pool filter. It should be carried out until the water runs clear through the waste line.


Without coping, the steel projecting from the pool's walls would be exposed, and water could get behind the pool shell. Coping is simply the cap for the pool's edge. It can be made of concrete, tile, stone, pavers, and other materials and can add an accent around the edge of your pool. Discover other functions of pool coping.

DE Filter

Not surprisingly, DE, aka diatomaceous earth, is the main ingredient in a DE pool filter. Swimming pools and spas need pool filters on them to keep the water clean and free of any dirt and debris. Discover why many pool owners consider DE filters to be the best kind of pool filter.

Gas Heater

While solar has been grabbing all the attention, gas heaters still account for most of the heaters in residential pools. These types of heaters are great for heating up your pool quickly, plus they keep the temperature of the pool regulated despite the temperature outdoors. While gas heaters are lower in cost to purchase and install, they tend to cost more long-term. They are not the most energy-efficient, and use more energy to run, plus are known to require more maintenance.

Main Drain

In most residential pools, two main drains are located at the bottom -- the deepest part of the swimming pool. The bottom of the pool slants toward these drains. The purpose of these drains is to take care of any dirt or debris that sinks. They are quite simply a suction device and are just one of the systems that helps keep the pool clean. These drains all have covers or grates placed over them to prevent people, their hair, or other objects from getting trapped in them.

Pumps and Motors

Working in tandem with the motor, the pool pump draws water from a pool or spa and somehow returns it back to the pool or spa. This is what keeps the water circulating in your pool. Find out how this happens and why it's an integral part of your pool.

Sand Filter

 What? Another type of filter for your pool? There are too many choices! This type of filter is actually the original and oldest kind of filter used for a swimming pool. These filters work by the pool's water being pushed through the sand, which then catches any dirt and debris particles. Sand filters are more cost-effective than some other pool filter types and require the sand to be replaced approximately every five years. 


Most residential pools have skimmers, which help with debris collection. Skimmers are located on the top inside of the pool's wall. They are a part of the cleaning system in that they "skim" out the debris that floats on the very top of the water. Skimmers grab everything from hair, bugs, leaves, flower petals, etc. in the conquest to keep the pool crystal clean. Find out the other functions of a skimmer and the other types of debris it collects (ick alert!).


Weirs are best friends to skimmers, and you rarely see one without the other. So just what are weirs? They are that little floating "thingy" inside the skimmer or the door that the water flows over or through. Weirs are a part of the protection system in keeping the pool clean. Find out more and why they are such buddies with skimmers.