At WiseGEEK, we're committed to delivering accurate, trustworthy information. Our expert-authored content is rigorously fact-checked and sourced from credible authorities. Discover how we uphold the highest standards in providing you with reliable knowledge.

Learn more...

What is a Crawl Space Sump Pump?

Anna B. Smith
Anna B. Smith

A crawl space sump pump is a device that drains excess water from a home without a basement. It is usually placed in a hole in the foundation of the house. It is typically installed as part of water-proofing, or water control, measures taken to drain rainwater away from the home. This can include surface water and groundwater seepage, which occurs when homes are situated lower than the water table. These pumps may be installed professionally, or by the homeowner.

A sump hole must first be dug into the lowest area of the ground where water collects. The crawl space sump pump may then be installed, either into the hole or to rest above it. A drainage line is attached, which runs from the pump to a separate location where the water overflow may be safely deposited. This can be either into existing city sewer lines or merely an area of lower elevation where the water run-off will not cause damage to the home or surrounding land.


The crawl space sump pump may be electrically-powered or may operate using the home's natural water pressure. Both styles of pump are typically equipped with a back-up power supply in the form of a battery pack. This allows the pump to continue to work even if the electric power to the unit is cut-off for any length of time.

In addition to a crawl space sump pump, other water-proofing measures can include installing a vapor barrier and using air conditioning in the area. Typically, water should not be allowed to collect in the crawl space of a home as it tends to cause a great deal of damage, both to the home's structure and to the health of its occupants. A sump pump can eliminate water that collects in the crawl space, while a vapor barrier prevents moisture from taking hold in the wood and cement commonly used to construct building foundations. Conditioned air, pumped through the area in question, also serves to keep it dry.

Sump pumps are made in a variety of sizes and are rated according to the amount of horsepower with which they operate, rather than the size of the tank. Most sump pumps sold for general home use range from one-quarter horsepower to one-half horsepower. The homeowner should estimate how much water the pump will remove during times of heavy drainage when choosing a crawl space sump pump. For instance, a one-half horsepower model can remove up to 3,000 gallons of water in an hour. A one-third horsepower sump pump is the most commonly used in homes.

Discuss this Article

Post your comments
Forgot password?
    • Worker