They are largely unnoticed and underappreciated.
They may rest quietly for days or weeks on end in the bottom of a pit until conditions demand they do their work to save our basements and crawl spaces from potential flooding.
Sump pumps are a key defense against Mother Nature in this part of the country, where we typically maintain a subgrade space in our homes, whether it be a narrow crawl space for mechanical systems or a deep basement area for storage and additional living space.
Basements and crawl spaces should be constructed with perimeter drains at the lowest level of the foundation, which is the ground the footing rests upon.
At a minimum, these drains surround the outside of the space, but a well-built home will also have an interior drain connected to the exterior loop, and all will run either to an adjacent ditch or low area outside the dwelling, or, more commonly, to a pit or crock located in the below-grade space below footing level.
We then install a pump in the crock, which operates automatically to remove any water that enters from the drain tile and exhaust it safely out of the building.
Fifteen percent of the homes in this country have such a groundwater management system, while fully 25% of basements will experience some degree of periodic flooding.
Note, we called this a groundwater management system. One of the pervasive myths regarding sump systems is that they are intended to handle surface water from the roof and ground above.
In fact, many homes will direct gutter downspouts directly into the perimeter drain system.
This should not be done for several reasons. To begin, directing roof water into the system can overload it and create flooding in the below-grade space.
The drain tile we installed around the perimeter is designed to conduct slow-moving water into the crock. If we invite fast-moving volumes into that system, we may then draw surrounding sand and fine clay into the pipe, which can not only block the drain but may undermine surrounding soils and, potentially, the structure itself as these soils are removed.
Surface water should be conducted away from the building through downspout extension pipes and sloped clay soils.
The groundwater we trust the sump to discharge may originate as surface water during heavy and continued rain events, snow melt, or water moving through the soils.
Water in the soil can create hydrostatic pressure that can literally lift a basement floor while it seeps up through gaps and cracks into the subgrade space. We locate the drain tile at the bottom of the structure so that it can intercept this water and safely direct it to discharge away from the building.
Many older homes still connect the sump discharge to the sanitary sewer, possibly overloading the sewer pipes in heavy rain events and causing backups into basements.
Many waste treatment facilities were designed to overflow into an adjacent river during such events, so we do not want rainwater or groundwater entering the sewer system and contributing to that situation.
In many jurisdictions, it is illegal to deposit sump water into the sanitary sewer, so we either conduct it to a storm water system or to a safe discharge away from the building, where it may then seep back into the soil.
The pump is connected to a vertical discharge pipe, with water passing through a check valve located at the basement floor level. Since many such pipes force the water through eight to ten feet of rise to get it out of the basement, we install the check valve to keep water in that pipe from falling back into the crock when the pump shuts off.
There are two types of pumps typically employed in sumps: a pedestal type that has the motor up out of the water and a submersible type that sits down in the water. A high-end pump may last 10 to 20 years or more in this situation, but owners are encouraged to periodically clean the crock bottom of any accumulated debris to protect the pump.
Backup or secondary pumps are often installed in case the primary pump fails. These may be powered by deep-cycle 12-volt batteries or even driven by pressurized water if the building is on a municipal water system.
This is not the place to go cheap. High-end pumps are expensive, but worth the investment when compared to what they accomplish. Newer pumps can also include remote monitoring applications for peace of mind when you travel.
Make it a point to have a professional plumber you trust examine your pump, discharge, and exterior line to ensure water is taken safely away from the home.
You can find several trustworthy professionals to help you at Insideoutsideguys.com.
Listen to the Inside Outside Guys every Saturday and Sunday on AM 760-WJR from 10 a.m.-noon or contact us at insideoutsideguys.com.
This article originally appeared on The Detroit News: Inside Outside Guys: ‘Sump pumps’ defend against flooding
Reporting by Ken Calverley and Chuck Breidenstein, The Inside Outside Guys / The Detroit News
USA TODAY Network via Reuters Connect
