If your basement occasionally floods, you probably already have a sump pump. Some signs your sump pump can't be repaired includes units which are noisy, experiencing electrical problems, or a total lack of service.
1. Noisy Units
If your sump pump is making a lot of noise the entire time it's running, either the impeller is bent or the motor is going out. Flip your unit and remove the screen, using your screwdriver. Inspect the impeller. If it is bent, you have no choice but to replace the unit.
2. Electrical Problems
If your unit gets power, but still doesn't work, it may have a broken wire or a connection may have come loose. Check the voltage with the electrical tester if possible. Electrical problems can be dangerous, especially around water. Replace the unit if needed.
3. Stops Working Completely
If your sump pump doesn't turn-on, first check that the unit is plugged in and getting power. Ensure the breaker hasn't tripped in the main panel box using the electrical tester.
Manually operate the float to see if you can get the sump pump to work. Check the float switch with your electrical tester to ensure it's showing current. If the float switch works, then your motor is probably burned out. Replace the unit.