How does a Swimming Pool Work?

Unless we’re actually involved with the construction of the pool, there’s a big chance that we really don’t know how everything is actually connected to each other. Yes, we might know what the individual role of each piece of equipment is and how to tell if they’re not functioning correctly, but do we know exactly how they’re all interconnected? Well, we’re going to answer that question today!

No time to read? Skip down to the TLDR (too long, didn't read) version.

As you can see from above, the water enters the pool’s circulation system via the main drain and the skimmer box (marked 1 and 2) and depending on the size and shape of your pool, you may also have some suction ports scattered around the pool (not shown on diagram) but these all lead to your pool pump.

Your skimmer box has a skimmer basket to prevent larger pieces of debris like leaves and such from entering your circulation system. Your main drains and suction ports will also have some sort of suction fitting that will allow water to enter but screen out debris and will also serve as a safety feature against suction-related accidents.

Tip: For more efficient skimmer basket pre-filtering, consider getting some Water TechniX pool skimmer socks! They're reusable and they reduce the overall load on your filtration system considerably!

Your pool pump is literally the heart of your pool since it is responsible for moving all of the water around the pool. Through the use of an impeller, your pool pump (marked 3) draws water in from the pool and pushes it through your pool filter (marked 4). Your pool pump also has its own basket as protection against any debris that may have slipped through your skimmer baskets or your suction fittings.

For further information on your pool pump, you can check out our in-depth guide on how pool pumps work right here.

Since we’ve started using analogies, might as well continue right? Your pool filter is literally like the kidneys for your pool. It takes in dirty water and filters it out. Water can pass through your filter media while larger dirt and debris particles are trapped within.

Water is pushed through from the pump (marked 3) and through the filter (marked 4) and then out to your pool’s heater, if you have one installed (marked 5) or your chlorinator, if you have one too (marked 6) or directly out back into the pool through the return jets (marked 7) if you don’t have a pool heater or a chlorinator installed.

Now if you have a sand pool filter, you will have a multiport valve which can be set to direct the flow of water. A multiport valve commonly has 6 settings which you can use to direct the flow of water.

• Filter - This is your “on” setting for your sand filter. Water flows through the sand filter normally and gets filtered by the media inside before being directed out towards the pool.
• Backwash - The backwash setting on your sand filter’s multiport reverses the flow of water, this dislodges the trapped dirt and debris inside the sand filter media in order for them to be flushed out.
• Rinse - After backwashing, the sand will be a little bit loose, the rinse setting recompresses the sand while directing the used water out through the waste port instead of being sent back to your pool.
• Recirculate - This setting bypasses the filter completely. This setting is used if you’re doing some sort of chemical treatment on your pool (like shocking or treating heavy algae blooms) and you want the chemicals to be fully circulated around your pool without contaminating your sand media.
• Waste - The waste setting on your multiport takes the water pumped in from your pool and directs it out towards the waste port. This also bypasses the filter media inside of the tank and is used when you want to partially drain your pool or if you’re dealing with heavy debris that you don’t want getting caught in your filters.
• Closed - This setting is only used when maintenance is done on your pool equipment or when replacing pool sand filter media. Warning: The multiport valve should never be set on “Closed” whenever the pump is running.

Multiport valves are the number one culprit for your pool sand filter malfunctioning, in response to that, we've prepared a Sand Filter Multiport troubleshooting guide right here.

If you have a pool heater, this should be installed AFTER the pool filter and BEFORE the chlorinator (if you have one). The reason for this is simple. You’ll want to heat up pool water after it’s been filtered, if it’s heated before the filter, you’ll lose heat while it is being filtered and the heated up water can damage your filter media.

The same reason goes for why the heater should always be before your chlorinator if you have one. The high chlorine concentration from a chlorinator can damage your heater elements and there’s no telling what sort of chemical reaction can happen if you heat up super chlorinated water.

If you have a chemical feeder or a salt water chlorinator, it’s usually the last piece of equipment in your pool’s circulation system before return jets send the water back out into the pool. It takes the filtered and heated (if available) water, doses it with chlorine and sends it back into the pool as clean, chlorinated water and then the cycle begins again!

Automatic pool cleaners or suction pool cleaners like the Water TechniX Rapid Automatic Pool Cleaner or the Pentair Rebel 2 utilizes the pressure from your pool pump to create the cleaning action required and they’re usually connected to your pool’s circulation system to the skimmer boxes (marked 2) with a special vacuum plate that’s designed specifically for your skimmer box model.

Robotic pool cleaners like the Zodiac Tornax TX30 don’t need any sort of connection to your pool system. Other pool cleaners like suction pool cleaners will require a strong pump to function properly and pressure-side pool cleaners require their own booster pump to function at all! Robotic pool cleaners are completely autonomous and they actually reduce the overall stress on your pool’s circulation system, extending the lifespan of your pool pump and filter.

Congratulations for reading through all that! But if you’ve skipped forward, here’s a quick too-long-didn’t-read version.

Pool Water -> Suction Ports -> Pool Pump -> Pool Filter -> Pool Heater -> Chlorinator -> Back to Pool.

You now should have a pretty good idea of how water flows all around your pool and how all of the equipment is all connected to each other!