Your pool's pump works hard to keep water clean -- after drawing water through the influent line, it passes the liquid through a strainer basket and then through a rotating impeller, which forces the water through a filter and finally back into the pool via an effluent line. Before any of these vital steps occur, however, the pump's motor must start. While pumps vary per make and model, some universal troubleshooting tips may help you get your pump powered on.
If your pump's motor doesn't start at all, a lack of power is a likely culprit. First ensure the pump's switch is set to its "on" position. Check your home's electrical service panel for a blown fuse or tripped breaker, and address these issues as necessary. Typically, swimming pool pump motors require 220 volts of electricity to operate; in this case, if your pump is connected to a 110-volt outlet, you may hear the motor hum but the pump will not start. During heat waves, your utility company may experience a power drop -- contact your electric company to confirm that the problem lies in your pump and not in your power supply.
A clogged impeller may prevent your pool pump from starting up. To remedy this, turn your pump's power off at the breaker, and then remove the pump basket lid and take out the basket. Carefully remove any visible debris from the disc-shaped impeller by hand until it spins easily. If you can feel debris in the impeller mechanism but can't remove it, contact a pool technician to dismantle the pump and clean or repair the impeller.
If you have a pool timer, ensure that it's operational and set to cycle as you want it to, otherwise your pump may not start. In particularly hot weather, a thermal overload can cause your pump to shut down during operation. Allow the pump to cool before restarting it. Likewise, clear the pump's air-intake vents of debris to remedy an overheating pump motor, which is prone to shutting down mid-cycle.
Beyond the Basics
If basic troubleshooting procedures don't address your pump's non-starting issues, consult your user manual for further guidance. If the troubleshooting tips therein still don't remedy the pump, contact the manufacturer for instructions or for a referral to the nearest authorized repair service. Issues such as corroded bearings or a faulty start capacitor -- often indicated by an oily discharge or white, powdery residue -- call for professional repair.