How To Drain a Fiberglass Swimming Pool
Basically, there are two methods to empty a fiberglass pool
depending upon which type of filter is attached:
Purchase a backwash hose from a pool supply store such as
attach it to the filter.
Diathamatious Earth (DE) Filter
The other method would be with a sump pump (preferably 2"), and be sure to run
the hose away from your property and your neighbors property. Be careful not to
let the pump continue to run after the pool is empty because it
Since even the smallest
swimming pool has at least 8,000 gallons of chemically treated water, you should
be cautious when determining where to dump the water. Some Townships even have
regulations, so you should check with your Township and find out before you
empty the pool.
These valves only exist in fiberglass swimming pools which have a standard
bottom drain resembling those used in bathtubs. Wall mounted bottom drains do
not contain relief valves.
As soon as the pool is empty,
use a shop vac to remove the remaining 6" of water that's pooling at the bottom
drain. Remove the two screws and lift-off the bottom drain. Again, use the shop
vac to remove the water that is still under the drain cover.
With the water removed, you can look inside to determine
which type of relief valve is there. One type has a "lug" nut that can be
removed with a ratchet wrench. Pull out the valve and set it aside with the lug
These work great when the pool is
new, but that is not when you usually need them. These type valves are located
inside a pipe that is next to, or on a 90 degree angle to, the drain pipe (that
goes to the pump). The drain going to the pump is the one that points directly
toward your pump and filter.
The hydrostatic relief valve is
inside the other pipe, just out of sight. Use the handle of a short stem screw
driver to reach inside the pipe and hit it several times, with the handle.
This will free the valve and let it open.
After removing a valve, place a
pipe into the valve (about 3 to 5 long) and put a hose through the pipe. This
will prevent the hose from laying on the bottom while you're working.
Bring the hose up over the top of the coping and attach a sump pump to
draw the water out from underneath the pool. This is just ground water, so there
is no chemical content to be concerned about. Point the water flow to a drainage
area away from the pool and other homes in your proximity.
Fiberglass Pool Stand Pipe
Many fiberglass pools had a
water problem during construction and, to the current owners good fortune, have
a "stand-pipe" located near the pump and filter. If this is the case, simply
remove the cap and place a long hose into the pipe, then attach the hose to a
utility pump and drain the underground water.
Quite often, a stand pipe
equivalent was used when the fiberglass pool was built and a high water table
was encountered. You may have a piece of black or white PVC emerging from the
ground on the side of the deck closest to the grass and on the same side of the
pool as the pump and filter. This PVC goes directly into a 4' by 4' by 4' pit,
or a 2' by 4' by 4' pit, underneath the pool that was filled with stone. This
PVC serves the same function as a stand-pipe and should be used as explained