The sump pump is a good way of keeping floodwaters out of the basement. However, the pump might not always do its job. Below are some of the reasons your basement might be flooded despite an installed sump pump.

Jammed Switch

The sump pump has a mechanical switch that triggers its operations when its surroundings are flooded. The switch is designed with a float ball that rises when the pump is flooded (to start the pump) and falls when the water level subsides (to stop the pump). If the switch is jammed with something like debris, it won't rise even if the pump is flooded, and the pump won't switch on.

Improper Sizing

If the sump pump is working at a slow rate and can't get rid of the water, then the problem might be the pump's sizing. Each pump has a maximum volume of water it can pump per minute. If the flood is sending more water than the pump is getting out, then your basement will continue to flood even if the pump is working.

Clogged Discharge Pipe

The discharge pipe channels water into the right direction for proper drainage. An extreme storm might flood your home and force some debris, such as flood debris, into the discharge pipe. The debris reduces the effective diameter of the discharge pipe and limits the volume of water the pump can get out of the basement.

Power Failure

The sump pump operates on electricity, so it won't be doing any pumping if there is no electrical power. This might be the case if, for example, a storm has damaged electrical infrastructure in your area. It might also be the case if an electrical malfunction in the house has tripped the circuit breaker.


Sump pumps, just like other plumbing installations, age with time. The mechanical parts wear out each time the pump operates. Therefore, the more the pump works, the faster it will wear out. The intrinsic deterioration of materials means even the least used pumps will eventually wear and experience reduced efficiency. You might notice such efficiency issues as your pump nears the 10-year mark where most of these pumps begin to fail.

Improper Installation

In rare cases, your sump pump might not pull its weight in terms of pumping efficiency because it was improperly installed. This might be the case if an unqualified person installed the pump. It might be, for example, that the sump pump doesn't have a check valve to prevent the backflow of water into the pump. Such backflow can force the pump to rotate backward and not pump out any water.

Call a plumber for help with various aspects of your plumbing system today.