Can An Inground Pool Overflow? Why It Happens + How To Fix It

Can An Inground Pool Overflow Explained

It may not seem like a big deal for a pool to overflow. After all, a pool is full of water. Nevertheless, can an inground pool overflow? If so, how much damage can a little more water really do? Depending on your soil type and the construction method used to build your deck, neglecting an inground pool overflow could be a very expensive oversight.

Can An Inground Pool Overflow?

Yes, it is possible for an inground pool to overflow. So what happens when an inground pool overflows? The water will often make its way between the coping and the pool structure and seep into the ground under the deck. This seepage may not seem like a big deal at first. However, when hundreds or thousands of gallons make their way into the earth under the deck, all sorts of issues can occur.

How An Inground Pool Overflows

One of the most common reasons an inground pool overflows is because the deck collapses from consolidation. The water will carry the smaller particles with it, and lead to a collapse of the deck over time. Another common issue in areas with expansive soils is for the deck to heave. Expansive soils are soil which change volume considerably from a dry condition to a wet condition.

In some places the movement of expansive soil may only be a quarter of an inch or less. In areas with highly expansive soils the movement could be a few inches. When the soil drys out the deck may settle back into place, but in many cases it does not and you’re left with cracking and an uneven patio surface.

How To Stop An Inground Pool From Overflowing

If overflowing sounds frightening, you probably want to know how to prevent it. Many pool builders don’t include overflow protection, either out of ignorance or as a cost savings. It’s silly though, since effective overflow protection can be done in most cases for a few hundred dollars.

Build In Preventive Measures

When constructing a pool, purpose-built overflow protection systems can solve this problem before it arises. These systems consist of a grate and pipe fitting connected to a drain pipe installed at the top of the pool, under the level of the coping or deck. There are also some skimmers which contain an overflow connection at their back which can accomplish the same effect. The idea is, if it’s raining and the pool is overflowing, the water level in the pool will never get any higher than the bottom of the overflow.

Can An Inground Pool Overflow and How To Prevent It
Courtesy of Atlantis Pools and Spa, LLC

The Ugly Side And How To Solve

One issue with overflows is how they look. In my opinion they can be located in an ideal spot that will be as out of the way as possible. For example, if you design a large patio area on one side of the pool, put the overflow on the same side. This way you aren’t looking at it from the main congregation area.

Also, keep in mind these overflows come in gray black and white, so they can blend with many color schemes. Note, if you have an infinity edge pool, you want to install the overflow on the infinity edge basin, not on the main pool itself.

How Pool Owners Can Take Extra Overflow Precaution

Even with an overflow installed, it’s a good idea to drain down your pool manually after large rainstorms. If your pool is winterized, it’s a good idea to drain your pool down if there is an excess of precipitation which causes your pool to overfill. The damage in winter can be severe, since it’s no longer just water percolation but ice formation which can be the cause of cracked tile and heaved coping, along with potential damage to the interior finish.

What Causes An Inground Pool To Overflow?

Now you know that pools can overflow and how to prevent it. You may also wonder, what causes a pool to overflow in the first place? Two major causes make up the majority of inground pool overflows. Here are these two issues and how to ensure your pool and the rest of your backyard does not fall victim.

Excess Rainfall

Most of the time, rain is the culprit. The typical pool only has a 3” ‘freeboard’ between the water level and the bottom of the coping or deck. This means if you get a large rainstorm, or a few rainstorms through the course of a week you’ll overfill the pool.

To avoid rainfall issues, keep your pool drained down so the water level is the middle of the tile. This can be done manually with the spigot most builders include at your pool equipment. First, attach a hose to the spigot. Next, run the hose into a storm drain or into a low lawn area where you can drain a lot of water to without causing any issues. Then, when you turn on the pool equipment and slowly open the valve, you will be draining your pool through the hose.

Alternatively, you can also use a small sump pump dropped into your pool. Whatever you do, you should set a timer so you check on the water level regularly. You don’t want to accidentally drain your whole pool because you started binging Netflix while draining rainwater out of your pool.

Broken Automatic Water Levelers

The other main cause of pools overfilling is broken automatic water levelers. Automatic water levelers are designed to keep the level of the pool up regardless of the evaporation which occurs every day. During extremely hot weather days, it’s not uncommon to lose 1/2” of water or more. Aside from replenishing, they also make sure that you don’t have too much water in the pool. However, like anything else, sometimes they break.

Automatic Water Leveler by Jandy
Courtesy of Jandy

The simplest of automatic water levelers operate in much the same way as a toilet. When the level goes down, the valve opens and refills the tank. Like a toilet, the float can get stuck and the water will continue to run. Unlike a toilet however, when a pool automatic water leveler gets stuck in the open position, there is nowhere for the water to go but overfill the pool. This is why we recommend electronic automatic water levelers like the Levolor K1100. These also require regular maintenance. However, they are less prone to the overfilling condition than the toilet float type.

Can An Inground Pool Overflow Bottom Line

There you have it, an inground pool can certainly overflow. In fact, overfilling your pool is easy to do. Although, with the proper prevention during construction and with proper maintenance throughout ownership, you should be able to prevent the worst of the damage caused by an overflowing pool. If you don’t have an overflow installed on your pool, make sure to keep track of rainfall. As a rule of thumb, keep your pool water level at the middle of the tile line.