Basement and Crawlspace FAQ: Sump Pit / Pump

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Sump-pump Care

Can you tell me how to care for my sump pump? Every winter I have to call a repair man after the first rain to get it started. What is the standard procedure to keep these things in good running condition?

Is it normal for a sump pit to completely drain even though the pump Normally, a sump pump does not require any maintenance. Certainly not yearly maintenance. In all probability, the pump’s intake port is sucking in dirt from the sump pit, and this is clogging the pump. The pit should have a liner, which prevents the earthen walls of the pit from eroding and depositing silt and tiny pebbles at the base. The pump should also be positioned so that the intake port is not at the base of the pit. Some sump pump manufacturers also make screens or filter boxes that can be installed in front of the pump’s intake. Check with the manufacturer of your pump to see if such optional equipment is available. You can also make one yourself using a window screen. However, you should periodically check the screen to make sure it’s not clogged.

Water-Powered Backup Sump Pump

I just moved into a new house. The builder installed a sump pit and pump in the finished basement as a precautionary measure against water seepage. The last hurricane that passed through this area flooded a number of basements because power was knocked out and sump pumps were unable to operate. Is there anything that I can do to prevent a flooded basement in the event of a power failure?

You can install a water-powered sump pump in the same pit alongside the electric sump pump. The pump utilizes municipal water, which is available even during a local power failure. The pump’s basic principle of operation is similar to that of an aspirator. That is, pressurized water flowing by a small opening will create suction. This, in turn, draws water out of the sump pit.

The cost of a backup pump system is expensive, but its cost is considerably less than the cost of repairing damage caused by flooding. The decision about whether to purchase a pump will depend on your tolerance of risk. It’s like buying insurance. What is the probability that a power failure and flooding will occur simultaneously? If you live in an area where this happens often, it makes sense to consider a backup pump system.

pop-mech_159.jpg emergency backup pump: sump crock; backflow preventer; guardian pump

Sump-pit Drainage

Is it normal for a sump pit to completely drain even though the pump suction is 6 inches above the bottom of the pit? The water is leaching into the ground and I don’t know if this is normal or if I have pit problems.

It’s not a question of normal or not normal. It’s a function of the porosity and drainage properties of the soil under the house. The fact that the water seeps into the ground indicates that the drainage below the floor slab is quite good. In this case, if water accumulates under the floor slab it will percolate into the ground rather than build up in the sump pit and activate the pump.

Even though the soil drains well, a sump pump is helpful to remove water that rises up from under the slab due to melting snow or heavy rain.

Sump-Pit Bottom

My basement has a sump pit with concrete sides and a sand bottom. In other words, the bottom is not lined with concrete or other material. When it rains, the water table rises, and my sump pump runs for four or five days straight. Would I have a problem if I closed the bottom of the sump pit?

Yes, you would have a problem. Your sump pit is working as it should. That is, it’s designed so that the bottom allows the entry of subsurface water. If the bottom of the sump pit is sealed, then as the water table rises, the water will press against the underside of the basement floor slab and seep through the cracks and open joints that often exist in basements.

On the other hand, if there are no cracks or open joints, depending on the level of the water table, the pressure the water exerts on the slab (known as hydro static buildup) could cause the concrete basement floor slab to crack and heave.

With your system, by pumping out the water that builds up in the sump pit, you are controlling the level of the water table so that it doesn’t rise to a point where it will press on the underside of the floor slab, thereby eliminating the problem of water seepage through the cracks into the basement. If the sump pit keeps the basement dry, our advice would be not to modify it.
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Updated: Saturday, December 24, 2016 17:21