A sump pump constantly running can be a good thing or, a bad thing depending on whether it is pumping water. Of course even if it is pumping water, constantly running is an indicator that the pump capacity is very closely matched to the flow of the ground water, and that should be a cause for concern. A slight increase in ground water flowing into the pit may overwhelm the pump and flood your basement or, a pump failure will as well. There are a few things you should check when you find a sump pump running constantly just to be sure that you are not close to being flooded.
One of the first checks that should be made on a constantly running sump pump is if the pump is indeed pumping water and operating close to its full capacity. There are sometimes things that can happen which can affect the pumping ability of a sump pump and it should be checked for proper operation. Often sand and silt flows into a sump pit carried in by the water, which then erodes the impeller vanes as it is pumped out with the water causing the pump to become ineffective. Sometimes impellers are made out of a metal that may corrode, which results in an impeller that has no vanes left to pump the water. A discharge pipe or hose can become clogged, broken underground or, in cold areas if it doesn’t drain dry after each pump cycle can freeze. When the discharge is blocked the sump pump deadheads and runs constantly usually with the water in the pit becoming warm or, even hot. Another common cause is the discharge pipe or hose coming loose from the pump in this case you will see water circulating in the pit. One of the requirements for installing a sump pump with many pumps is a 3/16” hole to be drilled in the discharge pipe a short distance above the pump before the check valve. When a sump pump pit goes dry during a period of drought it may dry out. When the pit refills with water the hole is needed to allow the air to get out of the pump allowing the pump to prime. If the pump is air bound because of water above the check valve holding air in the pump, water cannot reach the impeller so the pump will run constantly without pumping. In any case if you can see the water discharging from the pump it is a good indicator that the pump is operating properly.
If your sump pump is constantly running and you have found that the pump is pumping correctly you next should consider the ground water level, the ground water volume, and the pumping capacity. Sometimes the best thing to do is add pumping capacity and or, back up pumps, while other times simply raising the pump a few inches can allow the ground water to reach its own level without constant pumping being needed. During the dry period of the year is a good time to play with the pump level if the pump is running constantly even then. Shut off the pump and see how high the water gets in the pit. Naturally if the water comes up and is going to overflow into the basement, you have a very high water level and the pump is needed. However, frequently the water will rise to a certain level in the pit without flooding the basement or even reaching the bottom of the concrete slab. If the water level stops rising you should consider raising the level at which the pump turns on and allow the water level to remain at that level in the pit with the pump only turning on when it gets higher. You can also stretch this check into wetter periods of the year to fine tune the point at which the pump turns on. Sometimes people find that the pump was just set too deep into the water table causing it to pump water that didn’t really need to be pumped and when the pump was raised the running became infrequent and almost never ran constantly.
If your pump is running constantly and any time the pump is shut off the pit overflows then additional capacity and backup is something that you should strongly consider. The volume of ground water is too closely matched to your pumping capacity and any increase in ground water volume or, a pump failure as virtually guaranteed to cause a flooded basement. Back up pumps and power is strongly recommended, and the capacity of the back up pumping should be high enough to meet your needs.
You may want to consider other basement water proofing options as well such as curtain drains, regrading your property to divert water away from your home and installing drains for gutters and storm water to carry the water away from your home. Passive measures are always better than relying on a pump to get rid of the water.
Damage from a flooded basement can be very costly especially when appliances such as boilers, furnaces, HVAC air handlers, and water heaters can be severely damaged and often require replacement from flooding. The costs of using the services of an expert are trivial when you consider the cost of damage from flooding.