Article No: 102

2006-05-02 08:11:13
Sump Pump May Not Be Pretty, but it's a Basement's Most Important Equipment
By: Christopher Brooks


Ask most homeowners what's the most important equipment to their daily living and proper functioning of the home and answers will vary from heating or air condition systems to appliances or spas. Every homeowner has his preference as to what is the most vital equipment in a home. But how many would name the truly most important piece of equipment in a finished basement? Answer: The sump pump!

The sump pump's job is a major part of a basement survival from flooding water or foundation cracks. Consider the damage a failed sump pump causes. If the basement is finished, then carpet, furniture, paneling, baseboard trim and other items could be ruined. Even if the basement is not finished, areas of concern could be the furnace, hot water heater, mold and mildew and personal items. That's why the sump pump is the key component of a basement perimeter drain system. The effectiveness of the entire system depends on the successful operation of the pump. In fact, a malfunctioning sump pump causes most perimeter drain system failures.

Types of Pumps

A sump pump is used in basement applications to prevent the buildup of water around the concrete foundation. Essentially there are two types of pumps: pedestal and submersible. A pedestal pump has a motor outside the sump pit and a shaft extending into the pit to pump water. A float switch that is attached to the electrical circuitry of the pump will control the pumps on and off levels. Although pedestal pumps are still used, the majority of applications today will have a submersible pump.

Submersible pumps are quieter and more efficient than the pedestal pumps and allow for a completely enclosed pit. Submersible pumps can be found in various designs and make-up. Most submersible pumps are made of cast iron, plastic and stainless steel parts. These materials are more desirable then components such as sheet metal parts, due to the potential of extreme rust and corrosion. An important component of the sump pump is its switch. The switch should be rated for at least six starts per hour and free from obstructions (i.e. the switch hanging up on the side of the sump pit). The most commonly used switch is the type that travels vertically using a buoyant float that will rise with the water level and turn on the pump. For easy installation it's recommended that a vertical switch preset by the manufacturer be used.

Water Pressure

Water pressure takes its toll on any home - through the basement. "If water builds around or under a basement foundation, the water pressure can cause the concrete to crack, resulting in possible leaks. To prevent the water pressure, perforated drain tile is placed around the pit and gravity feed to the sump pit. The sump pit will have a pump installed that discharges the water into a sanitary main or storm water pipe," said Tony Renfro, regional sales manager for Zoeller Pump Co. ( in Louisville, Ky., manufacturers of a range of electric sump pumps.

"Some sump pits will be perforated with rock around the pit to catch the water that builds up under the foundation. Either application rather than drain tile pipe or sump pit with perforation, both will have small rock surrounding them to filter the water entering the pit from mud or particles," Renfro said. "Most sump pits will be between 15-inch to 28-inch in diameter and have a depth of around 24 inches. Anything smaller could cause the pump to run too often or not handle the volume of demand."

Essential Reinforcement

It is highly recommended that any sump pump pit application have a back-up system to the sump pump.

"It is amazing that most homeowners will spend thousands of dollars to finish or remodel a basement, yet not install a back-up system for extra insurance in the event of failure. Sump pumps are an excellent source for protection from water," Renfro said.

"It's recommended that a pump with a reputable name in the industry be used. However, the pump is an electro/mechanical product and will one day fail to operate. Because pumps are electrical, a storm causing an electrical outage can hinder the pump inoperable. Both of these situations can be combated with a back-up system."

Back-Up Systems

There are two types of back-up systems: water-powered, which runs off municipal water, and battery-powered systems. The water-powered system works well in low water volume applications and has proven to be very reliable. Water-powered systems use municipal water pressure to cause suction action through a pump body that is installed side by side or above the sump pump, and pulls the water from the sump pit. A float, mounted above the electrical pumps on level, controls the on and off level of the water-powered pump. If the water level reaches a point that causes the switch to rise, a valve will open and allow water to generate the suction action.

The battery back-up system uses a DC pump that mounts side by side the electrical sump pump or just above the sump pump. The DC pump will have a float switch that will be activated above the electrical pumps on level and will run off a 12-volt marine battery. A battery charger supplied with the system will maintain the marine battery and charge the battery after the pump has run.

Most battery back-up systems will have a high water alarm, monitoring lights for power and battery status, and all hardware to install the system. Both systems will require periodic inspection by unplugging the electrical sump pump and letting the back-up system run. Manufacturers' recommendations may vary. On battery operated systems remember to check the battery water level, unless the battery is maintenance free.

When installing any basement waterproofing system requiring a drainage element for channeling water, choosing the right sump pump for the job is vital. Familiarize yourself with different manufacturers' products to make the best choice for your next job. Additional information is available from the Sump and Sewage Pump Manufacturers Association (

Christopher Brooks is a Bucks County Pennsylvania freelance writer who writes about the home for trade and consumer magazines.