How Long Can a Pool Stay Empty? Risks of Draining It

How Long Can a Pool Stay Empty

Taking care of your pool in the summer is easy peasy. However, things may not go so swimmingly during the off-season when the trees start shedding leaves into your pool and the temperature starts approaching freezing conditions. Once this happens, you may feel tempted to drain your pool to make maintenance “easier”. Think again.

Draining your pool will not make things easier. Ironically, leaving your pool empty makes your pool susceptible to more damage than leaving the water in. The pool liner could crack or become wrinkled, the walls could collapse, and the pool shell can literally pop out from the ground. An empty swimming pool is more susceptible to structural damage from the elements.

Therefore, if you were wondering whether it is safe to drain your pool, and if so, how long you can leave it empty for, the answer is: don’t drain your pool; most problems can be solved while leaving the water in. And if you do drain your pool, then leave it empty for as short of a time as possible (1-2 days maximum) otherwise the problems mentioned above can happen.

Risks of draining your pool and leaving it empty

Most pools are very durable, but all of them are designed around having water in it. Leaving a pool empty, even for a short period of a couple of days, can cause damage such as:

  • Cracks and wrinkles in the pool liner
  • Leaks
  • Foundation damage
  • Damage to the pool accessories (heating, lights, pumps)
  • Damage to the surrounding area due to float

Repairing these damages is expensive and time-consuming. If you think you need to drain your pool, consult a pool professional first to get their opinion. Chances are, you don’t need to drain your pool. And if you do, you still need professional help for the reasons discussed below.

Concrete pools

Most inground pools are made of concrete. They are durable and have lots of customization options, but they are also expensive.

Since concrete pools are so durable, out of all the pool types they are the least likely to suffer catastrophic damage if left empty. However, it’s still not recommended.

Without water inside, it will be exposed to direct sunlight and other environmental effects that can deteriorate it and cause cracks and wrinkles to appear in the liner.

Concrete pools also run the risk of popping out of the ground (float) if there is sufficient groundwater underneath and it reaches a high enough point.

Without the weight of the water to keep it firmly in the ground, the pool will literally pop or float out of the ground, causing catastrophic damage to its surroundings. You cannot put the pool back in place when this happens.

Vinyl-lined pools

Vinyl-lined pools are the next most popular type of pool because of how affordable they are relative to the other pool types.

The shell of the pool is constructed using metal sheets, and then the pool is covered with a vinyl liner. The walls of the pool are not particularly strong; they are designed such that the walls can only withstand the pressure of the earth around it if it is filled with water.

Without water exerting an outwards pressure, the walls will literally get crushed by the weight of the earth surrounding it. If you must drain your vinyl-lined pool, you need to contact a professional so that they can use their specialized bracing equipment to keep the walls intact.

Fiberglass pools

The shell of the fiberglass pool is manufactured off-site, then transported on-location where a hole is created slightly bigger than its shape. The shell is placed into the hole and the shell is filled with water, and then the gaps around the pool are backfilled with soil.

Like a vinyl-lined pool, fiberglass pools are not very durable and cannot withstand the pressure that the surrounding earth exerts on it unless it is filled with water. Draining it will lead to catastrophic damage to the shell.

If you must drain it, call a professional to brace the walls before emptying it.

Above-ground pools

Above-ground pools can be purchased online or from a box store and installed by the user. However, you can also get it professionally installed if you’re worried that you’ll screw it up.

Some above-ground pools can be left outside during the winter, but not all. The ones that cannot be left out in the winter must be drained and disassembled to avoid the freezing cold of water.

You must make sure to completely dry each part and keep it in a climate-controlled space so that mold and mildew do not grow while your pool is in storage.

Some above-ground pools are installed within a deck, which can provide some protection (and makes it hard to disassemble). In that case, you should add the necessary chemicals in the water and put a winter cover over it.

Have a way to remove the water on top of the cover when it rains and unplug any electrical equipment such as a pump.

What are valid reasons to drain your pool?

As mentioned, it is generally not a good idea to drain your pool. Even if your pool closely resembles a swamp and you think your only solution is to drain it and refill it, you would be surprised at how effective skimming your pool, backwashing, vacuuming, and shocking it is. Pool shock can work wonders.

How do you think wastewater treatment facilities disinfect water? That’s right, they use some form of chlorine to make water clean again before they send it back to the environment. Chlorine is exactly the chemical we use to disinfect our pool water, and this chemical is capable of cleaning some seriously nasty stuff. Dirty water is hardly an issue worth emptying the pool for.

The only reasons serious enough to drain your pool are the following:

If your situation is not described above, then you can fix your pool’s problem without draining it.

Photo Credit: Michael Coghlan CC BY-SA 2.0