sump pump basement or outside the house?

9 years ago

We are building a house in the northeast. The builder is proposing an outside sump pump, but I have never heard of anyone in our area doing that, most people have it in the basement. Please help!!! I want to avoid a flooded basement at all cost. We have a small river nearby, but we are not in a flood zone. Thanks.

Featured Answer

indiana_th

9 years ago

We live in area with a high water table and we are in the process of building a new house. Our foundation contractor installed an exterior sump pump 2-3' feet below slab elevation, connected to an exterior foundation drain (exterior form-a-drain). It pumps the water before it gets into/under the basement and dewaters the area outside of the foundation. We also have an interior sump pump installed in the basement that is connected to the interior form-a-drain. The interior pump drains water under the slab.

Both have been operation since the basement was installed 3 months ago. We live directly in front of our build and I keep a watchful eye on the pumps. The interior pump runs more often but for shorter periods and the exterior pumps runs less often but for longer periods. (same pump and same diameter pit).

Comments (9)

renovator8
9 years ago
I don't know why or how a sump pump would be put outside of a foundation. How would the line be protected from freezing?

A sump pump should remove water that might collect under the basement slab. Exterior water should go into a foundation drain and travel by gravity to a dry well or daylight.

I would guess that an exterior pump would run quite often and have to be in the bottom of a structure that might cost as much as a dry well and need an unattractive access cover.

You should choose gravity over a pump whenever possible.
abekker
Original Author
9 years ago
So it seems that the two serve quite different purposes. The outside pump is more for rain water whereas the basement pump is more for the rising water table. Am I correct?
Related Professionals
Lexington Architects & Building Designers · Madison Heights Architects & Building Designers · Saint Andrews Architects & Building Designers · Newington Home Builders · Arcata Home Builders · Lodi Home Builders · Alamo General Contractors · Annandale General Contractors · Bartlesville General Contractors · Bay Shore General Contractors · Claremont General Contractors · El Monte General Contractors · McPherson General Contractors · Pacifica General Contractors · Westmont General Contractors
renovator8
9 years ago
Yes but you should not need both pumps.
Oaktown
9 years ago
Abbeker, that is my rudimentary understanding. We do not have a basement, but we have a bubble boxes, detention trenches and an exterior sump pump required by our local planning office and civil engineer for storm water management (runoff). Our contractor thought this was just over engineered and wants someone to take his bet that the pump never will switch on.
abekker
Original Author
9 years ago
Hmmm...it's quite confusing. If the exterior pump is supposed to keep water away from the house why would you still need the interior pump? My builder is proposing one or the other not both. He is pushing the exterior one, but I can't find too much info on that.
indiana_th
9 years ago
The interior pump drains water directly under the slab, which is from the water table rising from below. In our area I have seen too many basements with water issues and we decided to go with 2 as a precaution, one would have been fine.

The thinking on the exterior sump by contractors is to not let water into the basement. If an interior sump pump quits and water starts rising, the sump pit gives a direct flow path into the basement.
maire_cate
9 years ago
What happens during a power failure? Do you have whole house generators installed to insure that the pumps always run? I know they can also be connected to the municipal water supply and if the power goes out the pump will run off your water main, without electricity. But then you're paying for all that metered water.
abekker
Original Author
9 years ago
we will have a whole house generator