How to Drain an In-Ground Pool

 

Draining an in-ground swimming pool should not be done unless absolutely necessary, most often it is done because the pool is going to be resurfaced or repaired.  Most experts recommend asking a pool service to come out and do it for you. This is because once the pool is drained, if there is water underneath it the pool can actually heave up out of the ground or float. In fact, for many pools, it is impossible to drain them completely for this very reason.  The ground water trapped under the shell creates something called a hydrostatic force, which is strong enough to lift the pool right up.

 

All of that said, you can do it yourself if you are very careful.

 

Things You'll Need: Submersible pump Discharge hose

 

Step 1

First, check for a hydrostatic valve, which is located in the pool main drain. Remove it if there is one. If there is a plug there instead, remove it. Doing so might save your pool if it begins to do some hydrostatic floating.  Turn off your pool filtration equipment and pool lights at the appropriate breaker because if either turn on with the pool empty damage may occur to them.

 

Step 2

Attach the hose to the sump pump and lower the pump into the water at the deepest end of the pool. Make sure the other end of the hose is draining into a safe place, such as your home's sewer drain pipe. This is usually a small black, capped pipe in your front yard.

 

Step 3

Turn on the pump and begin to drain the pool. Check periodically to make sure the water is not overflowing out of the hose onto the street or your neighbor's yard. Try not to exceed 12 gallons per minute, as most sewer drainage pipes cannot handle more than that.

 

Step 4

If you live in an environment with a lot of ground water at this point you may want to remove water from the subdrain under the pool.  If the pool is equipped with a subdrain you can connect a pump to the exposed subdrain pipe and pump water from under the pool.

 

Step 5

Stop pumping as soon as you can. It is best to leave as much water as possible in the pool to prevent both hydrostatic floating and cracking. Some pools, especially fiberglass, cannot handle the outside pressure well when they are not full of water.

 

Step 6

Fill the pool again as soon as possible. If you let it sit empty too long, you will most likely ruin it and the surrounding area as well, especially if it is concrete or granite.  The pool surface needs to remain wet in order to maintain it's adhesion to the pool shell underneath and to keep from shrinking and cracking.

Tags: Draining pool water, Submersible pump, main drain, hydrostatic floating, cracking