There are many reasons why a pool owner might want to drain their pool: to get rid of unsanitary water, to clean the pool walls, to do some light repairs, or simply to not have to worry about the water freezing during the off-season.
However, leaving a pool empty for too long can cause damage to the liner and even the entire pool structure itself. The question is, how long can one leave a pool empty for before such damage occurs?
The general consensus is that you should not drain the pool because the liner can experience negative effects in as short as 15 minutes. You can partially drain it below the skimmer for some quick cleaning and maintenance to the plumbing system, but do not drain it any more than that. Leaving a pool empty can cause a whole host of problems such as shrinking of the liner or structural damage caused by the soil around it or the elements.
Will draining an above ground pool damage the liner?
Is your pool water an unsightly green? Are the walls stained? Does it smell funky? Is there too much debris in it? You probably feel a strong urge to drain it so you can clean it.
However, keep this in mind: most pool problems can be solved without draining it. You would be surprised at how effective shocking, vacuuming, and filtering the water is at turning it from a cesspool to a clean and clear pool once again.
Simply having dirty pool water is, surprisingly, not a good enough reason to drain your pool. Even minor damage to the liner or the pool structure can get fixed without draining the pool.
Before you decide to drain your pool, you should get a second opinion. Call a pool repair company and see what they think. If there is a serious problem that warrants draining the pool, you should let them do it for you.
A “serious” problem in this case means a problem that cannot be repaired unless the pool is drained. They have bracing equipment that can help the pool structure retain its shape even without water in it so that it won’t become deformed or collapse.
Why you shouldn’t leave the pool empty
The liner will get damaged
If you have a vinyl liner, then draining the pool will cause the liner to start drying out and shrink within as quickly as 15 minutes.
Once the liner has shrunk, even if you expose it to water again, it will never have the same elasticity and suppleness it once had. It will forever be a bit smaller and will need to be stretched over the pool structure which can cause it to tear.
Furthermore, the sun’s harsh UV rays will not only cause the liner to dry out faster, but can also cause it to become brittle.
Now if your plan is to replace the liner, then I suppose you can drain it without caring about the old liner. But even then, perhaps you should not be the one to drain the pool.
The pool structure can get damaged
Furthermore, whether you have an above-ground or inground pool, your pool is designed to be structurally sound when it has water in it, and it is actually very vulnerable if you ever empty the pool.
Particularly for inground pools and semi-inground pools, the water is necessary to keep the pool walls from collapsing under the weight of the surrounding earth. It exerts outward pressure to balance the inward pressure the soil and groundwater exerts on it.
A common problem that inground pools have is called float. This is when enough water fills the space between the pool and the ground underneath it. Think of your pool shell like a boat, and the groundwater underneath like the ocean.
If there is sufficient groundwater due to heavy rain, and your pool is not being held in place with water, then your pool can start to get lifted out of its position like a boat during high tide.
As you can imagine, this is a disastrous scenario and worrying about some silly liner damage will be the last thing on your mind if this occurs.
Once a pool has popped out of the ground, it will cause severe damage to its surroundings and to make matters worse, it can’t be put back into the ground.
As for above-ground pools, an empty above-ground pool is susceptible to strong winds and other extreme weather events that can cause the uprights to collapse or the pool structure itself to be literally blown away.
It’s time-consuming and expensive
Draining and refilling your pool can literally take hours. The water bill will also be enormous, and the costs will only be higher if you mess anything up while draining the pool and you need to replace some parts.
There is also the issue of your liner shrinking in as fast as 15 minutes. The idea that you can “quickly” drain the pool and then refill it before it has time to shrink is a pipe dream. This process will literally take hours.
If you’re dead set on draining your pool, then you should also be willing to replace the liner while you’re at it, because it will get damaged for sure.
Not recommended: draining the pool anyway
I can’t force you to do anything. If you truly feel that draining the pool is the only solution to your pool problem, then at least follow the steps below to minimize the damage to the liner and pool structure.
- Drain your pool the night before if the next day is cloudy with minimal wind. The sun and wind will cause evaporation to occur much faster, so draining it the night before and doing any cleaning/repairs/refilling the next day as early as possible before the sun rises or the wind picks up is ideal.
- Use a drainage pump with a hose attachment for above-ground pools. Direct the hose to a storm drain or a downhill slope facing away from your pool so that the water doesn’t seep underneath the pool and damage the foundation.
- Read the pool’s user manual to learn how many gallons of water can be removed per hour. This will help you better time your operation so that you can avoid the sun’s peak hours.
- Work quickly. You need to work quickly because your pool liner can start shrinking at any point. Again, draining the pool is NOT recommended, and anything you do here is at your own risk. It’s a bit of a Hail Mary, but if you’re lucky, you may be able to solve your problem without your liner sustaining too much damage.
Again, I highly recommend you consult with a pool expert to see if the problem can be fixed without draining the pool. And even if you need to drain the pool, better let the pros handle it, because it’s too easy to cause damage to the liner and pool structure.