In many homes, the sump pump plays a critical role in keeping the basement dry. If the device is showing signs of trouble, you'll want to fix it as soon as possible to avoid flooding.

A sump pump consists of a pump situated in a water-filled hole called a sump pit, typically located in the basement or crawlspace. Lee Wallender, writing for the home design site The Spruce, says the pump is automatically activated when rising groundwater elevates the water level in the sump pit above a certain height. Once enough water is pumped out to bring the water level back down, the pump shuts off.

It's not uncommon to hear the sump pump turn on when a rainstorm or other event causes the water table around your home to rise. The pump can also help drain water if a ruptured pipe or other problem causes flooding. But if a sump pump is running continuously or failing to keep water at bay, it's a sign that something is wrong with the device.

Water in the basement is the most obvious sign that your sump pump is not working properly. While a number of factors can cause this issue, one possibility is that the pump is not properly sized for the job it has to do. Matthew Stock, writing for the foundation repair and waterproofing company U.S. Waterproofing of Rolling Meadows, Ill., says the pump may not be able to expel water fast enough to keep up with groundwater intrusion. If this is the case, you should upgrade to a more powerful pump.

Since sump pumps are electrical devices, they can easily be knocked out of commission during a power failure. A battery-powered backup pump can help protect your home when electricity is not available. Tony Rubeo, owner of the water damage restoration company ReNew Services of Indianapolis, says it can also help to have a generator available or to use surge protectors to protect the sump pump from damage.

During cold weather, the discharge lines used to expel water from around your foundation may become frozen. These lines can also become clogged by debris. A grated opening can help prevent blockages, but the grade of the lines may need to be adjusted to keep water from collecting and freezing. The inlet valve may also be clogged, in which case the pump will not register that the water table is rising.

If the pump should be turning on but is not doing so, the problem might be electrical. Wallender recommends checking the fuse or circuit breaker to see if there is a problem with either component.

While the pump will periodically turn on if it senses a higher water table, it shouldn't be constantly running. This may occur if the pump is undersized, since it will need to operate for a long time to get rid of the water. Waterwork Plumbing of Ferndale, Mich., says this problem may also be the result of a broken or missing check valve, which keeps water from returning to the sump pit instead of being expelled outside the home.

A pump may run continuously if its float switch has become stuck or tangled. Terry's Plumbing of Pittsburgh says a mechanical float will activate the switch when water carries it upward and shut it off when the sump pit's water level recedes. If the switch becomes stuck in the "on" position, the pump will run continuously until the switch is freed.

While some noise is to be expected in the operation of a sump pump, the device shouldn't create any noticeably peculiar sounds such as rattling or grinding. Waterwork Plumbing says these noises are usually associated with a motor problem.

In some cases, the sump pump may be defective or improperly installed. Rubeo says some problems can include an inadequately sized discharge line, the lack of a check valve, or installation in a dirt or gravel floor, which increases the possibility of blockages.

Like any home system, the sump pump comes with a limited lifespan. Wallender says the devices usually come with a warranty that lasts between three and five years, and that it is often recommended that a sump pump be replaced after 10 years. Stock says it is best to get a new pump every five to seven years.

The lifespan of a sump pump will depend on a variety of factors. Waterwork Plumbing says these include how frequently the pump is turned on, how far the water must travel before it is expelled from the home, and the overall quality of the pump.

Sump pumps will also have a shorter lifespan if they are not properly maintained. Maintenance steps include testing the electrical connection, making sure the pump has not tilted from an upright position, and pouring water into the sump pit to make sure it activates the pump. Wallender says it is best to conduct this maintenance at least once a year, during the late winter or early spring to avoid times when the sump pump will be subjected to greater demand.

Rubeo says some sump pump manufacturers recommend that the device be activated at least every two or three months to ensure proper function. Your inspection can also include checking to make sure water is being expelled, clearing any debris from the lines, replacing batteries on backup pumps, and seeing that the motor and float are working properly. You can also pour a vinegar solution into the sump pit, as this will run through the pump and help clean it.