Trained Eye


Filling Holes in Sump Pit


I installed a sump pit, 15 years ago, as back up to remove weeping tile water from the floor drain catch basin in case of a sewer back up. A back water valve was also installed to protect the basement bathroom, at the same time.

This sump pump well has been dry for all these years as it is to be used only in an emergency.  But lately it has developed two pin holes in the bottom corner fold of the corrugated plastic well, which slowly fills up with water. Due to the very slow seepage, the water gets stagnant before the sump pump starts to drain it.

I would really like to plug these holes and make the pit dry again. I am having difficulty patching the holes as drops of water are always present and the area can never be dried. I have tried all kinds of rubber patches, glues, candle wax, etc. I even tried melting the plastic with a soldering iron to cover the hole but to no avail. Even aqua cement will not work as it will not stick to the plastic. Old time plumbers that I have consulted do not know what to suggest.

Any assistance or suggestions would be very much appreciated as I am out of ideas.

Thank you very much. 


It is refreshing to see a homeowner who has an excellent understanding of the purpose and function of a sump pit and pump installed in an older home. Too many homeowners have had these systems installed after a sewer back-up, often at the request of insurance companies, and don’t have a clue how they are supposed to work. While your knowledge of this home component’s need is right on the money, your desire to keep the pit dry may be somewhat misguided. I will offer some suggestions and recommendations which may eliminate your problem, but not in the manner you may expect.

As previously stated, the purpose of your sump pit and pump installation is simply to prevent weeping tile water from flooding the basement in the rare case that a sewer back-up would cause your backwater valve to close. The backwater valve is simply a one-way valve installed in the drain pipe, beneath the basement floor slab, that allows material to flow from the house drain to the sewer pipe outside, but not in the reverse direction. This should prevent sewage from backing up through your basement bathroom drains and the basement catch basin floor drain should the city sewer become blocked. If this occurs during a heavy rainstorm, as is often the case, the excess rainwater will overflow from the catch basin into the sump pit. To allow this to work properly, there should be a short pipe installed just below the surface of the basement floor slab that connects the sump pit to the catch basin.

I understand your desire to eliminate stagnant water from the bottom of the sump pit, to minimize odours and possibilities for mould growth, but its presence is not necessary a bad thing. The few holes that have developed in the plastic pit are letting in a small amount of excess water from the soil beneath your floor slab. Removing this moisture from the soil may be beneficial to help prevent frost heaving of your concrete floor slab. Your problem is simply the lack of sufficient amounts of water to allow the pump to regularly clear this from the pit. In my view, this is the true defect, which may be fairly easy to rectify.

One problem with sump pumps installed as sewer back-up protection, such as yours, is the lack of regular use. Sump pumps are designed for periodic operation, when engaged by an internal or external switch activated by a certain volume of water in the pit. If this rarely occurs, as you have observed, the pumps may seize or not properly function when called upon. If a pump has sat mostly dormant for several years, it may not respond properly when it is needed most, during a one-time sewer problem. For this reason, I always recommend that homeowners regularly operate the pump. In your situation, this could solve both these concerns with one solution.

The best arrangements that I see with late installation sump pumps incorporate one or more of the existing weeping tiles directly into the pit. This diverts some of the regular weeping tile drainage water to the sump pump, which should ensure periodic operation, typically during the Spring thaw. This not only reduces the amount of water going into the storm sewer system, but also runs the sump pump as designed. This weeping tile connection may be very difficult for you to install after all these years, but there are a couple of other possibilities that should accomplish the same objective.

If a few small holes in the bottom of the sump pit are enough to let a small amount of water in, drilling several more near the top of the plastic pit, above the height where water activates the pump, may cause it to run more frequently. If there is excessive moisture under the floor slab, draining it into the pit and discharging it to the exterior can only help with water management. If the soil beneath your basement floor is not wet enough for this to occur, run a hose or dump a few pails of water into the pit several times a year, during the warm months, to run the pump. This will serve not only to test the pump, but will remove the stagnant water creating the problems in the first place.

The bottom line is that you may not be able to completely dry your sump pit by blocking the holes, but that should not be a necessity to ensure proper function and maintenance. A focus on maintaining enough water in the pit for periodic operation will be a better and easier way to approach the issue.




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#110-2025 Corydon Ave
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R3P 2G9