Infinity, Negative, and Zero Edge Pools: What’s the Difference? (2024)

If you are in the process of adding a new swimming pool to your own backyard and you want a pool that looks more luxurious than the standard pool design, then you should consider a pool with an infinity, negative, or zero edge.

But wait… what’s the difference between these edges and types of pools?

If you are like us when we were in the process of designing and building our pool, we were getting confused about these terms and all the other lingo we had to learn about a new pool.

If you are considering these types of edges for your pool, read on below to find out what these different edges are and what the right option if for your pool!

Short Answer: Yes, infinity, negative, and zero edges can mean the same thing because they share the same essential concept in pool design: all of these edges create a type of pool that has the optical illusion of pool water seamlessly blending into the surrounding area and/or extending to the horizon.

Unlike a regular pool that has a water line below the clearly defined edges of a pool, an infinity pool design creates a visual effect of water extending beyond a pool edge or edges.

You may also come across the terms for an infinity pool, like perimeter overflow pool, vanishing-edge pool, knife-edge pool, overflow pool, and disappearing edge pool to describe the same thing as an infinity edge, negative edge, or zero edge pool.

An important thing to understand before we get into the following sections is understanding how an infinity pool works.

Simply, an infinity edge works by creating an edge of the pool that is slightly below the water line of the pool. This allows the water of the pool to slowly flow over this edge into a trough (also called a lower basin, catch basin, or catch pool) that catches the falling water. The water in this trough is then recirculated and pumped back into the main body of the pool, where it will flow over the infinity edge, repeating the process.

Now that we have established that these terms can mean essentially the same thing to the overall look of a pool, let’s walk through some of the key things factors for these edges. These factors can create some key parts of your actual pool design and also why a pool contractor might use a term infinity edge vs. negative edge vs. zero edge.

These factors are:

• Edge location and elevation
• Edge length
• Edge slope (smoothness of spillover water)
• Trough size
• Cost
• Maintenance

✅ Note: In the following sections, I will simply call everything an infinity edge unless I need to make a clear point to use a different name like negative edge or zero edge.

Probably one of the most important factors to consider is where you want an infinity edge in your pool.

Usually, an infinity edge will be at the back (or far) edge of the pool to give the look of the endless pool. Usually, this edge will have to be in a spot where there is enough elevation behind the pool for the water to flow over the edge and into a trough below. Typically in a design like this with water overflowing an elevated edge, it is most common to use the terms infinity edge, negative edge, or vanishing edge.

You can also have an infinity-edge look without elevation too. This is accomplished with water flowing over an edge of the pool into 2-3″ opening that runs the length of the edge (in some cases, this can be larger if the trough is covered by something like a trench drain). The water flows through this small opening into a semi-concealed trough that is about a foot below the edge.

On the other side of this 2-3″ opening is typically the decking of the pool. The end result is that it looks like the pool water is at an even height and right next to the pool’s decking. Some pool builders will call this design a knifes edge, perimeter overflow, or zero edge pool given how seamless and edgeless the pool looks.

An infinity ledge can be any length. For some pools, this could be just one distant back edge of the pool. For others, this could be the entire perimeter of the pool to have a seamless edge look.

How long the infinity edge can be is determined by your available useable outdoor space, the overall style of pool you want, and your budget.

Keep in mind that a longer infinity edge will require a larger trough and a greater volume of water that needs to be recirculated (this will result in a greater cost – more materials and equipment).

For this part, we are talking about the top of the pool wall on the infinity edge that has water flowing over it. This top part can have three different types of slopes:

• Upward slope (the high part of the slope is the outer edge of the wall)
• Downward slope (the high part of the slope is the edge of the wall closest to you in the pool).
• No slope (the top of the wall is flat)

​For the first two options, the slope is generally around 15 degrees, but this can vary based on your pool’s design.

The important thing to know about these slope options is this:

• Upward and downward slopes will result in a smoother spillover effect of water flowing out of the pool into a trough.
• No slope infinity edges will have more ripples and have a bit rougher spillover.

The smoothness of the spillover water is important: a rougher spillover will reduce the appearance of an “endless pool” because the rough water can show the edge of the water.

👉 Tip: If the smoothness of the spillover water is important to you, make sure you talk with your pool designer about the right option for you.

Additionally, these slopes can be called by different names and can result in some confusion around the names used for an infinity pool.

• Upward slope: This is often referred to as a true infinity edge.
• Downward slope: This is often referred to as a reverse infinity edge.
• No slope: This is often referred to as a negative edge.

As you can see, the shape of the slope can carry a different name (e.g., negative edge), but it is still used to create an infinity pool look and feel.

Now that we have covered various aspects of the physical edge, let’s move on to the trough of an infinity edge. To quickly recap, a trough (also called the catch basin) is an area that will catch the falling water from an infinity edge.

The size (and location) of the trough is dependent upon two things

• Size of the infinity edge
• Style of the infinity edge

Size of the infinity edge: All else equal, a trough will need to be as equally as long as an infinity edge. Additionally, a long infinity edge will mean a greater volume of water will fall into a trough, so a large may be required. Depending on the size of the pool and the infinity edge, this trough may need to be about 1/3 the size of the main pool!

Style of the infinity edge: This goes back to the placement and elevation discussion above. If the pool water spills over the infinity edge from a high elevation to a lower elevation, more than likely, this trough will look like a small, separate pool at the bottom of main pool. If you wanted to, you could design your pool to have this trough as useable pool space (this will end up looking like multi-level pools).

On the other hand, if you want the edge to look flush with the decking of your pool or other surrounding areas, this trough area will be recessed and partially hidden between the pool and underneath the perimeter of the decking of the pool. So, you really won’t see the trough except through the small 2-3″ opening for the pool water to flow through. In some cases, this trough can be underneath a plastic trench drain gate that is flush with the edge of the pool and decking.

Regardless of the style, design, size, edge slope, trough size, etc., adding any type of infinity edge to a pool will be expensive. Here’s why:

• A separate pump is needed to recirculate water from the trough to the main pool
• Additional plumbing, electrical, gunite, coping, tile, etc. is needed to build out the trough
• Additional construction may be needed to adjust the elevation of the outdoor space

At a minimum, you should expect that an infinity edge will cost an extra $10,000 – $15,000 to your overall pool costs. This estimate is for an infinity edge with a trough that looks like a small pool.

If you want the infinity edge to be flush with the edge of your decking, you should expect a minimum cost of $20,000 – $30,000. The reason for the higher cost here is that this construction process is more complex to perfectly construct the narrow and concealed trough that needs to run along the perimeter of the pool.

Pool owners with infinity edge pools should expect to have a bit more maintenance on their hands. The extra maintenance is due to having to keep the trough clean – algae can grow here too! Additionally, the extra equipment, especially the pump, adds another piece of equipment to care for and clean.

The amount of maintenance will depend on the size of the infinity edge and trough. Troughs that are concealed along the perimeter of a pool can be harder to clean because there is a small 2-3″ gap to access and clean the trough in some areas. Or this concealed trough is below a trench drain gate that needs to be removed.

Below are some additional considerations for an infinity edge pool.

Construction Timing

Adding any type or size of infinity edge will add time to construct a pool compared to constructing a typical pool. This extra time is needed to set the shape, gunite, and tile perfectly right to have an even spillover of water on the infinity edge. Also, additional time will be needed to build the trough.

The time needed will vary based on the ultimate shape and design of the pool, but this can be anywhere from a few extra days to a few weeks of extra time across different construction phases.

Design Options

As you consider adding an infinity edge to your pool, there are several design options you can include or factor in with your infinity edge.

• Functionality of the edge: If you want to be able to rest on the ledge or use it as a point to exit the pool (especially for zero-edge types that are flush with decking), you may want to consider making this pool wall in this area wide enough to do this.
• Water features: If you are planning on having other water features like a waterfall, scuppers, or sheer descents, balance how these will look with the appearance of the infinity ledge. You may be somewhat limited on where you can place these if you want an unobstructed landscape view since these will need to be placed on a raised wall.
• Fire features: Adding a fire bowl can not only add ambiance and appeal to your pool, but it can also help illuminate the infinity edge at night.
• Glass wall: You may have seen some pools that have a glass pool wall where the infinity edge is. This can be a great option if your outdoor space has a vantage point for this see-through look.

Below are some frequently asked questions about infinity edge pools:

Why Do People Want an Infinity Edge Pool?

The biggest reason why people have an infinity edge is that it can make a pool look stunning and luxurious! The look of an infinity edge in your pool can take the style of your pool and your backyard design to the next level. Infinity pools are definitely a step above the design of traditional pools.

Why People Don’t People Have an Infinity Edge Pool?

Not all backyards and outdoor spaces have the proper space or elevation to have an infinity edge. In most cases, a side of the pool will need to be elevated, either naturally or constructed, in order for the water to flow to a lower trough. You also need additional trough space to hold the overflowing water and recirculate it to the main pool. And as we covered above, adding an infinity edge isn’t cheap, which is another main reason people might not get an infinity edge even though they have the space.

What is the difference between negative edge and infinity edge pool?

It is true a negative edge pool and an infinity edge pool are terms that are used to mean the same thing: a pool edge that creates the optical illusion of pool water seamlessly blending into the surrounding area and/or extending to the horizon. But there can be a very small difference for some people on these terms for two reasons:

1. For some, an infinity edge pool is only used to describe a pool with the look of the pool’s water blending into a larger body of water like a lake or ocean, giving the appearance that the pool’s water infinitely extends into the larger body of water.
2. For some, a negative edge describes an edge with no slope, whereas an infinity edge has an upward-sloping edge.

Why is it called a negative edge on a pool?

The term “negative edge” refers to the absence of a visible edge in a pool, creating the illusion that the water is flowing away from the pool and leaving a negative space.

Is a zero edge pool the same as an infinity pool?

At a high-level, yes a zero-edge pool and an infinity pool are the same thing: these are pool designs that create the optical illusion of pool water seamlessly blending into the surrounding area and/or extending to the horizon. There is a slight difference in how some people may use these terms.

If the look of the pool is to make the water level of the pool flush with the pool decking, some people may refer to these only as zero-edge, knife-edge, or perimeter overflow pools. For some people, the term infinity edge will only be used for a pool that has water flowing over an elevated edge that creates the appearance of the pool water extending into the surrounding landscape or another body of water.