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Sump Pump Installation in Basements, Crawl Spaces, and Exterior Drainage

Prevent basement flooding by installing and maintaining a sump pump.

Tom Silva helps a homeowner with a sump pump installation in the basement of their home.

There’s no better way to prevent a basement flood than with a sump pump. Although it isn’t the most DIY-friendly of projects, installing a sump pump in your basement, crawl space, or backyard will prevent your home from warping, rot, mold, and mildew caused by water damage.

A sump pump uses a submersible float that rises and falls with the water table. When flooding causes the float to rise, a switch automatically turns on and the pump begins to extract water and drain it through a pipe to the outdoors.

Sump pump installation generally requires a professional. These are the steps involved:

Sump Pump Installation Process in 8 Steps

A professional showing a homeowner how to install a sump pump in the basement.
  1. The process begins with setting the sump basin upside down on the basement floor and marking its outline. (When choosing a place to install the pump, factor in a proper drainage plan and a proximity to a ready power source.)
  2. Next, use a demolition hammer to chop through the concrete floor and dig a hole deep enough to set the sump basin inside it, flush with the floor.
  3. Before setting the basin in the hole, wrap its exterior base with filter fabric. This will prevent silt from clogging the pump motor.
  4. Then, after the basin is placed inside the hole, put several layers of gravel inside it, then lay a stone paver on top of the gravel. This will keep gravel out of the pump and provide a firm platform for it.
  5. A one-way check valve will need to be connected to a PVC pipe to run up the wall and out of the basement. While the arrangement of this pipe will vary from home to home, its universal function is to carry water up and out of the house. When drilling a hole for the pipe in the house wall, use a hole saw and seal the area around the pipe with a paintable caulk. This will provide a watertight seal. The PVC pipe should extend outdoors, and empty through a downspout. If the grading of the land is insufficient for proper drainage, either invest in regrading the yard or in an even longer downspout to ensure water is fully carried away. Some homeowners may be tempted to simply run a drain line from their sump pump into a municipal storm drain, however most locales won’t allow this. Before installing a sump pump, check with your town to see which drainage options are permissible.
  6. To finish the installation, fill in the crevice around the sump basin with new concrete, mixed in a trough with a hoe.
  7. Fill in around the basin to the top with concrete and smooth it off with a pointed trowel.
  8. After powering up your pump, test it by filling the basin with water. If you ever need to replace the pump, this can be done by simply switching off the power to the unit, disconnecting the old model from the discharge valve, reconnecting and leveling a new pump, and testing it the same as you did upon the initial installation.

Installing Crawl Space Sump Pumps and Exterior Sump Pits

Crawl space sump pump in a basement. Photo by Eric Axene

Not all sump pumps are built the same. The simplest sump pumps are plugged into an outlet, but there are other models that come with backup batteries that run the pump even during a power outage. This secondary power system can come in handy during inclement weather, and the battery should be replaced every two years.

How Do You Install a Crawl Space Sump Pump?

Installing a sump pump in a crawl space requires slightly different preparation and materials. The earth inside your crawl space may not be even, and below-grade water may create pools of standing water in low spots. When placing the basin, consider easy access, and as with the basement install, a proper drainage plan, and a ready power source. The process for installing the basin and discharge system are the same, until it comes to finishing the hole for the basin. Rather than pouring concrete, it’s recommended that pea gravel be added up to the lip of the basin for proper drainage.

How Do You Install an Exterior Sump Pump?

Sump pumps can even be installed to resolve exterior drainage issues. They work the same as they do inside your home to drain standing water from outdoor entertaining spaces and lawns. They can also protect your foundation by redirecting water away from the house. Because the exterior pump will need to serve a larger surface area than most basements, a professional contractor may opt to dig inlet lines and catch basins that will feed into the sump pit from different points around the landscape.

From there, most sump pits have lines that drain into the street gutters, but check your local municipality to confirm permissibility. Installing an exterior sump pump should always be performed by a professional, as obstacles like gas and sewer lines must be worked around. Exterior sump pumps are best suited for climates with mild winters. Water freezing and expanding in the system can prematurely ruin the pump. Without this kind of interference, most sump pumps last for approximately 10 years.


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