Selecting and Maintaining a Sump Pump
This article was originally published on September 17, 2008 and expired on November 10, 2008. It is provided here for archival purposes and may contain dated information.
If you have a house with a basement or crawl space, you likely have a sump pump. From time to time, these pumps need to be replaced.
"Knowing what type of pump works best for your situation will keep failures, flooded basements and other hazards to a minimum," says Duane Friend, University of Illinois Extension natural resources management educator.
There are two main types of sump pumps: pedestal and submersible. A pedestal type pump has the motor attached to the top of a shaft. The motor is not designed to be under water. A pedestal pump works well in small diameter basins.
Submersible pumps are designed to sit in the base of the sump basin, below water level. These pumps are more adapted to larger sump basins and are typically quieter than pedestal pumps.
Sump pumps usually come with an automatic on/off switch. A float switch is the most common. As the float rises with rising water levels in the basin, the pump is started after the water rises to a certain level.
To determine the size of pump needed, you must know three things: how much water will need to be pumped, how high the water will need to be pumped, and the length and size of pipe.
"Do not assume that having a large horsepower pump will be the best choice," says Friend. "A large horsepower pump in a small diameter basin will cause the pump to frequently cycle, shortening pump life. At the same time, you need a pump that will keep up with maximum drainage. Pump capacity charts are available from professional installers and pump manufacturers; the information can also be found on the web."
When installing a sump pump, it is usually recommended that a check valve be installed. This valve prevents water left in the outlet pipe from flowing back into the basin. Some valves can be attached to the sump pump itself, while others are placed farther up the outlet pipe. If the valve is not attached to the pump, it is recommended that a 1/8-inch air relief hole be drilled into the outlet pipe, between the valve and the pump. This hole prevents a condition called an air lock, where the pump will attempt to work but cannot pump water. Be sure the air relief hole is placed so that any water that comes out of the hole will remain in the drainage basin!
"A dedicated electrical circuit should be used for the pump," advises Friend. "Most pumps have a high amp load when starting. Do not use an extension cord to plug the pump into the outlet."
To maintain a sump pump, periodically check the system. Make sure the float is free of obstructions. Observe the outlet to make sure water is actually being pumped. Listen for unusual noises when the pump is running. If the pump runs just a few months of the year, fill the basin with water and make sure the system is operating before its normal operation time begins.
If a sump pump fails and water gets into the basement, do not attempt repairs without first turning off the power to all basement outlets. If water has completely covered the basement, it may be necessary for an electrician to turn off the power at the meter. To minimize long-term indoor air quality concerns, dry the affected areas as soon as possible. If flooding is severe or long lasting, dry wall, carpeting and other materials may need to be replaced.
If a properly-sized, quality pump is used, it should last three or more years, with 10 years being reasonable, according to the U.S. Department of Housing and Development. When purchasing a pump, look for one that is built and tested according to Sump and Sewage Pump Manufacturers Association (SSPMA) specifications (see website below).
For more detailed information on properly sizing a sump pump, get the U of I Extension fact sheet "Sizing Up a Sump Pump" at www.wq.uiuc.edu/Pubs/SumpPumps-8-17-05.pdf. Additional information on sump pump installation can be found at the SSPMA website, www.sspma.org/pubs/index.html.
Source: Duane Friend, Extension Educator, Energy and Environmental Stewardship, firstname.lastname@example.org
Pull date: November 10, 2008