Q–My crawl space and basement are prone to flooding during periods of heavy rain. The sump pump sometimes vibrates and fails to work. When it does work it often does not keep up with the incoming water. What might be wrong? Is there a backup system available? What size pump should work well for an average size house?
A–Sump pump failures are the bane of many a homeowner. I have seen thousands of dollars worth of damage caused by just 2 to 3 inches of water in a basement. Often, the failure of the sump pump can be traced to simple installation mistakes. High-quality sump pumps can operate for years without a major malfunction. I know this is true because I have installed hundreds of them.
The leading cause of failure in most sump pumps is the switching system. The switch often fails to turn on because the pump has shifted inside the sump basin. The float that operates the switch then can lodge against the side of the sump basin and not turn on.
It’s also not uncommon for a piece of debris to interfere with the action of the pump switch. Check to make sure your pump switch and float arm assembly move freely.
The vibrations and inability to pump on occasions can almost always be traced to “pump air lock.” When a sump pumps turns off, the water in the discharge line between the pump and the check valve drains back into the sump. If the pipe between the pump and the check valve is solid, the air in the line will compress the next time the pump tries to empty the sump basin. This compressed air can prevent water from leaving the pump. A 3/16-inch vent hole in the side of the discharge pipe inside the sump solves this problem. Check to see if the discharge line inside the pit has this hole. If it does, make sure it isn’t clogged.
Your sump basin may be too small. All too often, people use a simple 5-gallon bucket as an inexpensive sump basin. This is inadequate. A residential sump basin should have a minimum inner diameter of 18 inches. It should be at least 22 inches deep. Small and narrow sump basins cause switching failures and more frequent pumping cycles.
A sump pump backup system might be a good idea. Often flooding occurs when sump pump needs are the greatest. A soil-saturating rainstorm may cause a localized power outage, so the pump doesn’t go on when it’s needed most. Powerful battery-operated sump pumps can solve this problem. These pumps get their power from standard high-performance automotive batteries. They come with alarms that tell you if the battery is low or partially discharged.
If you don’t like this solution and your home has city water, you can use a backup pump that operates on regular water pressure. These pumps will usually get you through the emergency until regular power is restored. By using less than $1 worth of water, you can save thousands of dollars in damage to your belongings.
If your current pump has a 1/3- or 1/2-horsepower rating, you should be OK. Higher horsepower pumps will pump more water. Look for pumps that have cast iron or heavy metal housings. Cast iron can dissipate heat buildup much better than a pump with a plastic or thin metal housing. Price is usually an excellent indicator of a pump’s quality.
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Have questions about the remodeling process? Write to Tim Carter, c/o The Chicago Tribune, P.O. Box 36352, Cincinnati, Ohio 45236-0352. Questions will be answered only in the column.
For a list of manufacturers of battery- and water-powered backup sump pumps, pumping capacities, sump discharge piping tips, and other sump pump installation information, send $2 and your name and address to Tim Carter at the above address. Ask for Builder Bulletin No. 190.
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