It is often called an infinity pool, but it is necessary to specify which kind of overflow we talk about. There are, indeed, four principal ones, and even if the principle of functioning is nearly the same, the aesthetic effect is very different.

You can find here more details about the functioning of the overflow swimming pool . But we remind you, below, the basic principles.

The operating principle

The overflow is often put forward for aesthetic reasons, but it is not its only strong point!

In the skimmer pools, the water is sucked about 10 to 30 cm below the surface . However, it is the surface of the water that is the most polluted: dust, pollen, dead insects, hair and sunscreen, among others. In overflow pools, the superficial layer of the water is caught by a tank from where a filtration pump sucks it. It ensures a healthier water.

The under-coping overflow

It’s probably one of the oldest type of overflow out there, and it still exists in countries like Morocco or Tunisia. Originally, the system ensured the adequate skimming of the water by injecting fresh (water) into the pool, which forced the surface water ( which is dirtiest) through the overflow channel and into the sewers. The fact that none of it was ever re-used meant a huge daily consumption of water that would, of course, be unacceptable by our current standards.

Today, the use of water tanks ensures that this type of overflow can still be used. However, much like the older version, the use of an under coping overflow certifies both an ideal recycling of the water (much more effective than skimmer pools) and less evaporation compared to other types of overflows.

Only downside: its aesthetic appeal is limited, nearly inexistent. This is why it is most often recommended in projects where the client doesn’t want any other type of overflow, or in cases where an overflow channel already exists.

The Infinity overflow

Because of its unparalleled aesthetic impact, this is, without a doubt, one of the most well-known type of overflow in the world.

It is most often used for steep terrains and, thus, usually, only occupies one side of the pool. By looking out from the patio or the inside of the house, you get the illusion that the water disappears off the edge of the horizon.

As shown by the diagram, the success of this type of overflow is dependant on the overflow channel being completely invisible (and silent) from all angles. You can only guarantee this by having the adequate profile. Anything less, and you will also inevitably have to deal with a cacophony of noises set on by the resulting waterfall. If, however, some of you are looking for this kind of realistic waterfall, it’s quite easy to do. Don’t worry !

This is, by far, our favourite type of overflow. In fact, most projects we have worked on have it in some capacity. And don’t forget that it is not necessary to have a sea view. To see for yourself, have a look at our image gallery.

The Deck level overflow

So called because of the precise alignment of the water with the level of the deck, this  perimeter overflow is generally used to create a calm, relaxing atmosphere. Also, it allows people to visualize the entire water surface, regardless of where they stand. To many people, this creates the illusion of a mirror.

If the overflow channel is well-made,  it is perfectly silent. Until now it was the reserve of the public swimming pools:  a steel grating allows the water to escape to the storage tank.  For the private project, it is better to replace the gratting with a small gap at the junction between the deck and the pool. This second version is very aesthetic.

For example, to build the swimming pool below, we have used the latter method.


But, regardless of the method you choose to use, it is important that you do not forget about the two symmetrical slopes situated near the edge of the pool. They make sure that rain water, or deck washing water doesn’t get mixed in with the water from the pool. Inversely, they also guarantee that most of the pool water doesn’t leak out onto the deck.

In conclusion, this kind of overflow is perfect for patios, flat grounds without particular view. And remember, it is suitable for any pool shape, geometric or free.

Mixing different types of overflows together?

The answer is, in reality, quite simple: Absolutely! It is perfectly acceptable, and possible, for you to engage in a form of collage of different overflows. If you require a more isolated area in your pool ( jacuzzi, kiddie pool, etc…), we would even recommend using a skimmer system alongside the overflow one. Why? Because, as we have already seen, different overflows and systems serve different purposes and are always better suited to certain needs. If you want a pool that can satisfy a variety of needs, and respect the complex characteristics of your landscape and lifestyle, mixing and matching is the best option for you.


The above photo as well as the featured image  illustrate two separate occasions where we decided to mix a deck level overflow with an infinity edge one. As you can see, this was the only solution to simultaneously ensure the visibility of the entire water surface and respect the clients’ steep terrains.

And which one is your favorite? See other examples on our gallery

How to choose the right overflow system ?

This is, after all, the whole point. Although the choice is initially aesthetic, it is also necessary to take account of the site topography, the position of the swimming pool on the ground, its location in relation to the house, the view, etc. Shortly, you have to consider many parameters . If you have any doubts at the time of the choice, do not hesitate to contact us. We put our years of experience to work for you.

The End