How Does a Swimming Pool Work? (2024)

The cool thing about a swimming pool is they all work in the same manner. No matter the size, shape, or added features, they all use a combination of filtration and chemical treatment to consistently keep the water clean and healthy. But really, how does a swimming pool work?

As a new pool owner, you might not have a handle of the ‘ins’ and ‘outs’ of your pool yet, and that is okay.

There are two different types of pools, above ground and inground. Aboveground pools are the cheapest construction option and the easiest to construct as well. They are typically made from prefabricated kits and are easily installed by a pool professional. On the other hand, in-ground pools are made from gunite, concrete, fiberglass, or vinyl liner. While the design of these pools is different, they all rely on the same basic plumbing and filtering system.

The Flow of Water

Water in a swimming pool needs to circulate through a filtering system to remove dirt and debris. During normal operation, water flows through the filtering system through two or more main drains at the bottom of the pool and multiple skimmers around the top of the pool. In your pool, the water is pulled through the main drain, the skimmer, and the vacuum port. Skimmers collect and skim water on the surface by propelling the water and screening out the largest debris in the strainer basket. This allows for an evenly heated pool and uniform chemical treatment.

Afterwards, it is sent through the pump, the filter, the heater, and then returned back into the pool through the return fittings. You may need to add an additional pump for waterfalls and jets.

Your Pump and Filter

In order for a swimming pool to be free from algae and other harmful contaminants, the pool must have a working filter. However, without a pump, your filtering system will not work and your pool will get too dirty to use.

The Pump

The heart of the pool system is the pump. The electric motor on the pump spins the impeller inside the housing and drives the water from the various drains. Once the water is pulled through the skimmers, it flows through the wet end portion of your pool pump. The wet end portion of your pump includes the strainer lid, strainer o-ring, strainer basket, diffuser, impeller, and a shaft seal. The water passes through the pump and out of the discharge of the pump into the filter.

The Filter

During the filtering operation, the dirty water from the pool comes through the filter’s inlet pipe and heads to the water distribution head inside the tank. As gravity pulls the water down, depending on the type of filter you have, either sand, cartridge, or diatomaceous earth catches the dirt and debris. Pressure gauges at the inlet and outlet give you an idea of how much blockage the filter currently has. If gauges show much greater pressure on the inlet pipe than the outlet, it is an indication there’s a lot of collected debris and it is time to backwash or clean your filter cartridges.

Balancing Your Pool Water

Although the filter system handles all the hard work in keeping your pool water clean and healthy, water chemistry handles all the fine touches. A healthy chemical balance is essential to not just your pool but also to the rest of your pool equipment. A pool filled with untreated water is a perfect harvesting place for pathogens and other disease-carrying microorganisms. Pools with the incorrect chemical balance can damage other parts of your pool, irritate your skin and eyes, and cause your water to become very gray and cloudy. Thus making your pool experience a rather unpleasant one.

Chlorine

The most popular disinfectant is chlorine. When chlorine is added to the water, it reacts with the water to form various other chemicals. Chlorine is typically prepared in liquid, powder, or tablet form. Pool experts generally recommend adding chlorine just after the filtering process, using a chemical feeder. If added directly into the pool, chlorine tends to be too concentrated in certain areas and not evenly distributed.

When chlorine reacts with water, one of the most notable chemical reactions is hypochlorous acid. One problem with hypochlorous acid is that it is highly unstable. It degrades when exposed to sunlight and may combine with other chemicals to form new compounds. Often times chlorinators include a stabilizing agent, like cyanuric acid, that will form a more stable compound once it reacts with the chlorine.

Heating Your Pool

No one likes to swim in a dirty pool or a cold one for that matter. Swimming pool heaters have increasingly become very popular and a “must have” for pools in certain areas in the country. There are various methods to heat your pool: heaters, heat pumps, solar panels, or solar covers. Many of our customers use a combination of these to reach the maximum heat potential while using the least amount of energy. Still, pool heaters are the most popular. Both propane and natural gas pool heaters are good for heating a pool quickly and are able to maintain a constant water temperature.

Heat Pumps

Pool heat pumps are a more efficient, environmentally friendly way to heat a pool. It can save a pool owner a lot of money in operating costs, however, unlike gas heaters, a heat pump’s effectiveness is dependent upon the weather. They operate by extracting heat from the outside air, increasing the heat with a compressor, and then delivering the heat to the water. If the temperature is below 45 degrees, the heat pump will not function. So, depending on the average temperature of where you live, a pool heat pump may or may not be the best choice for you.

Gas Heaters

Gas heaters create a flame on a gas burner that heats a metal heat exchanger. Once your pool water flows through the filter it ends up at the heater next. Gas burns in a combustion chamber that heats the water as it passes through. Over time, the circulated pool water will warm up and maintain a constant temperature

The longevity of each pool equipment varies from pool to pool depending on your location, how often you run each system, and also the water chemistry in your pool. We offer an extensive list of how to guides for pool owners that provides step by step tutorials and videos to help you along the way. Remember, when in doubt, call a pool professional. There is nothing worse than spending money to fix something that could have easily been solved from day one.

How Does a Swimming Pool Work? (2024)

FAQs

How Does a Swimming Pool Work? ›

The water in a pool is constantly in motion thanks to the heart of the pool system, a pump powered by an electric motor. The pump moves the water through the skimmer located at the top of the pool and the drain located at the bottom of the pool. Skimmers and drains act as veins, leading the water to the filter.

How does a swimming pool water system work? ›

Equipped with an electric motor, the pump has an impeller that drives water through the skimmers (found at the top of a pool) and the sumps (found at the bottom of a pool) take it to the filter. The clean, filtered water is then piped through the return nozzles (a series of small valves placed around the pool).

Where do pool drains go? ›

Drains and Skimmer

The main drain is the primary way that water is drawn from your pool into the pump and filter. The main drain is located on the bottom of the pool in the deepest part. Most pools have one, but larger pools may have multiple main drains. Main drains must be protected by an approved cover.

What is the principle of swimming pool? ›

The basic idea is to pump water in a continual cycle, from the pool through the filtering and chemical treatment systems and back to the pool again. In this way, the pumping system keeps the water in the pool relatively free of dirt, debris and bacteria.

Where does swimming pool water go? ›

During normal operation, water flows to the filtering system through two or more main drains at the bottom of the pool and multiple skimmer drains around the top of the pool. The main drains are usually located on the lowest point in the pool, so the entire pool surface slants toward them.

Do all inground pools have a main drain? ›

Main drains are not required in an inground swimming pool, however, they are strongly recommended and can be extremely useful in some circ*mstances. The advantages of main drains are to give you the ability to drain the water from your pool without the use of a sump pump. This is useful when replacing your pool liner.

What happens to the water in a swimming pool? ›

The water in swimming pools is recirculated through a treatment system in which chemicals are added to kill microbes and maintain pH. The water is filtered to remove dirt and other particles. Because about 1% of the water is lost daily through evaporation and other mechanisms, freshwater must be added regularly.

Can pool water be drained into the sewer system? ›

Draining your pool into a sanitary sewer system is the preferred option. Most in-ground pools have a drain line connected to the sewer line. This should be used only after the pool water has been dechlorinated. If your pool is not connected directly to the sewer, locate a sanitary sewer cleanout on your property.

How does swimming pool plumbing work? ›

In conclusion, swimming pool plumbing is a complex system that is essential for maintaining clean and safe pool water. The system's components, including the pump, filter, skimmer, return line, valves, drain, pipes, and fittings, all work together to circulate water through the filtration system and back into the pool.

Why do pools have two main drains? ›

One of the most well known updates was to require all pools to use two drain suctions as a part of the installation (assuming a drain is installed). The reasoning for this is that if one drain is blocked by a person's body, the other drain can compensate. Swimmers are better protected from entrapment with two drains.

What is the golden rule in swimming? ›

Never Swim Alone

Always ensure someone watches you when you swim, even adults.

What is not allowed in a pool? ›

Bottles, glass objects, drinking glasses and sharp objects are not permitted in the pool area. Trash should be placed in the proper receptacles located throughout the pool area. Food is allowed only in designated areas of the pool facilities. All swimmers must wear bona fide swimming attire.

What are do's and don'ts in a swimming pool? ›

NO running, jumping, or pushing one another on the pool decks or along the pool apron. NO spitting or littering within the premises. NO footwear beyond the no-footwear zone or on the pool deck at all times. NO food and drinks (except for plain water) shall be consumed in the pool premises at all times.

How long can water sit in a pool without chlorine? ›

Water in a pool without chlorine can start to become unsafe in as little as 24 to 48 hours.

Where does the water go when a pool is drained? ›

For instance, most municipalities will require you to run your pool water through your home's sewer cleanout line so it will flow to a water treatment plant. Others might allow you to send all that water down the storm drains that line your street. Municipalities may also have water chemical composition regulations.

How does water flow through a pool? ›

The Pump. After it leaves the pool through the skimmers and main drains, water flows to the pump. The pump is the heart of the circulation system, providing the suction and pressure to keep the water moving. A pool's plumbing system is generally categorized into two sections, the suction side and the pressure side.

How does pool water get to the filter? ›

How Your Filter System Works: The Short Answer. Your pump pulls the pool water from the skimmer(s) on the pool wall and the main drain(s) on or near the bottom of the pool. The water flows through the pump to the filter, which removes dirt, debris, and (if the filter is good) bacteria.

How does water circulate in a swimming pool? ›

A: The pool pump is the heart of the circulation system. It pulls water from the pool across the skimmer & main drain, then pushes it through the filter to remove impurities.

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