Sump Pump Prep School

When a sump pump fails to do its job, the result can be an expensive mess.

A couple inches of water in a finished basement can cost hundreds of dollars when you factor in ruined carpet — and much more if a piano or other valuables are damaged in the flood. That’s why a backup sump pump is a good idea, says Ken Cotten, president of and the inventor of several basement-waterproofing systems. If your primary pump stops working for any reason, a backup pump immediately takes over. But like any protective measure, these units come at a cost.

Most back-up pumps are battery-powered and are installed right next to the primary pump. They can be set up with their own discharge pipe or joined to the existing discharge. Water-powered pumps are another option, as long as your water comes from a local utility (not a well or cistern) with at least 40 psi of pressure. Cotten says the efficiency of water-powered pumps has significantly improved in recent years. The best units remove 2 gallons of wastewater for every gallon of water you use, according to manufacturers’ claims. “The beauty of these pumps is they don’t require batteries or any of the maintenance and periodic replacement that go with them,” Cotten says.

The price of peace
Despite their offer of added protection, neither battery- nor water-powered backup-pump systems are very common, Cotten says. Each year he sells 2,500 primary AC sump pumps but only 125 battery-backup pumps and even fewer water-powered pumps – only eight in 11 years. The problem, he says, is money. In his own newly built home, a dual-pump system would have cost $1,600, and the price for a three-pump system (with two AC pumps and a battery backup) would have been much higher.

“Battery-backup pumps will only run for a limited time, so I chose to buy a water alarm for $150 instead,” Cotten says. “It automatically calls me, as well as three additional numbers if needed, to let me know I have a problem.” Cotten’s backup plan is to quickly fix or replace the primary pump should it fail, or if the problem is a power outage, to plug the primary pump into a generator — a practical solution for someone who works close to home and has friends or relatives nearby.

The more expensive battery-backup systems, such as the Basement Watchdog Big Dog model, can match the capacity of primary pumps, whereas the average backup pump will only handle about one-third of the volume.

However, Alan Schulman, president of Glentronics Inc. (the largest manufacturer of battery-backup pumps), takes a different position. He is a strong advocate for battery-backup pumps and has devoted much of his career to making these systems reliable. “The most common problem with battery-backup systems has typically been a neglected battery. When called upon to perform, it doesn’t work, or it performs poorly,” he says. To prevent this, Schulman’s systems incorporate battery monitoring. If the battery needs water, is old and discharged or is without electricity (due to being unplugged or because a circuit breaker is tripped), an alert sounds and the monitor panel tells you what to do to remedy the situation. It will also notify you when the pump has been activated. Higher-end units will even tell you if the pump is clogged or broken and how much backup run time remains.

If you opt for a water-powered backup pump, buy one that installs over the sump pit, not in the sump pit. This unit (Zoeller’s Home Guard Max) is mounted to the primary pump’s discharge pipe; others may be joist-mounted.

Schulman also says that “continuous run-time” ratings, the common measure of backup systems, are misleading. While it’s true that continuous run time for battery-backup systems averages about seven hours, he points out that the vast majority of situations require only intermittent pumping. “At a more normal 25 percent-on cycle, the battery backup will operate for two or three days. Even given a heavy-duty, 50 percent-on cycle, a system will get about a day,” he says. You can add a second battery to double the run times – or even hook up the system to a car battery (with the car running outdoors, of course).

Battery-backup systems are not exorbitantly expensive. The retail price of Schulman’s Basement Watchdog models runs from $150 to $475, and batteries cost $80 to $125. The backup pump can be installed by a homeowner who has moderate DIY skills. Costs for water-powered pumps fall in the same range, but the installation is typically more complex and costly because it involves running a water-supply line and installing the appropriate valves. Furthermore, running the supply line may not be feasible if the basement is finished.

Combo systems include both a primary and a backup pump and are preplumbed. They are also designed to fit inside most existing sump pits.

Schulman is dead-set against water-powered pumps for environmental and safety reasons. He believes that using thousands of gallons of clean drinking water to pump wastewater out of basements is an unsound practice. He also worries that many installers will not incorporate the requisite backflow-prevention devices (check valves and integral atmospheric vacuum breakers), potentially contaminating drinking water due to backflow from the sump pit. His biggest concern, however, is that too many water-powered pumps running during a storm might lower the municipal water pressure, not only making the water-powered pumps inefficient, but also leaving firefighters without sufficient pressure at the hydrant. In fact, several municipalities have banned water-powered pumps.

The generator-backup approach
Using a generator to keep a sump pump running during a power outage is a workable backup plan, but you (or someone you trust) must be at home to start the unit. Although automatic gas-powered generators can be installed to turn on automatically when needed, they are too expensive for the average homeowner.

One benefit of the generator approach is that it enables you to run other appliances during a power outage, but it is not without inconvenience. First, generators must be properly maintained. You cannot leave one unused and forgotten for months and expect it to start right up when you need it. Second, you need to have gas service or a propane tank on site for generators that run on natural gas or propane – or store vast amounts of gasoline or diesel fuel for a gas-powered model. Finally, if flooding occurs because the primary pump fails or can't keep up, a generator won't solve those problems; a backup pump will.

In addition to sump pumps, there are a number of ways to prevent water from entering your basement. Here are several methods you can use without investing a lot of time or money.

  • Grading: The area around foundations is backfill soil (often containing all sorts of construction debris and rubble), and the ground eventually settles, resulting in a grade that slopes back toward the house. This is a common cause of water infiltration, especially if the house's gutter system is not working properly. The remedy is to inspect the perimeter of the house and regrade as necessary. (Ideally, the ground should drop 6 in. within the first 10 ft. away from the foundation.)
  • French drains: If your house sits at the base of an incline, water during a heavy rain (or snowmelt) may run directly toward it. To intercept the water and stem infiltration, consider installing a French drain. This entails burying a perforated drainpipe in gravel at an angle to divert the flow away from the house. Be sure to wrap the pipe with landscape fabric to prevent it from becoming filled with sediment.
  • Dehumidifiers: These machines do not stop water from infiltrating your basement, but they will draw moisture from the basement air that would otherwise cause mold and mildew to flourish. If you run a drainage hose from the dehumidifier to a floor drain or sump pit, you won’t have to manually empty the unit – a frequent chore during humid months.
  • Gutter systems: A poorly functioning or improperly installed gutter system is worse than none at all. Gutter systems are intended to keep rainwater from accumulating at the base of your foundation, but the gutters must be regularly cleaned so the downspouts do not clog. In addition, the downspouts should have extenders at the bottom so rainwater is ushered away from the foundation. A surface extender is one option. A less visible option is an underground downspout system (see drawing).

The UnderGround DownSpout system from includes a debris filter and a bubbler pot that disperses water onto the lawn or in a garden.