Generally, when pipes in a pool are clogged, the issue is the main drain of the pool. Frequently, you will be able to resolve this problem on your own without calling in a swimming pool technician. If this is the problem you can take care of it yourself with special attachment for your garden hose. If the problem is other smaller pipes in the system, you may have to bring in a professional.
Close the suction pipes that lead into the skimmers. These pipes are very seldom clogged and almost certainly not the issue. However, to ensure that no water can work its way out of these pipes instead of forcing the obstruction clear in the main pipe, you need to close off these outlets. Usually, they can be twisted or rotated shut.
Attach your hose to the drain attachment. You will need to measure your drain's dimensions and take this information with you to a pool supply store to ensure that you get the right device for your pool. They usually cost about $20.
Place the hose with the attachment on or in the drain, depending on the model. If it goes inside the drain, then you will need to remove the drain cover. If not, you can place it over the drain. It will be easier to do this if the pool has been partially or wholly drained, but if drought restrictions will prevent you from refilling your pool, then you can do this while there is still water in the pool.
Turn your hose on full blast. The pressure of the water going down the main drain should be sufficient to clear the clog. You will know it is clear because when you lift the attachment off or out of the drain, the debris will spill into the pool where you can vacuum it out. You may have to do this as many as 10 times to fully dislodge the debris and clear your pipe completely. If you still do not have a functioning main drain after this, then you will need to call in a professional to see if the pipe itself has collapsed instead of just clogging.
Vacuum the pool. You will probably have a large lump of dirty leaves swirling around in your pool once you have dislodged the clog. Vacuum this dirty mess up, and then you will be ready to enjoy your pool once again.