Standing water in your home can lead to structural problems and health hazards. One solution is a sump pump.
The problem of moving standing water from one place to another has preoccupied engineers for thousands of years. Historians report that even Archimedes worked on the problem. Fortunately for modern homeowners, technology came to the rescue in the late 1940s with the development of the sump pump.
Sump pumps solve the problem of standing water, which is a headache for homeowners with basements built into the ground with a high water table or poor drainage. A flooded basement can cause expensive water damage and even be a health hazard.
Out in the yard, sump pumps help drain standing water in low-lying areas, which can render those areas unusable and create breeding grounds for mosquitoes.
So what exactly is a sump pump, and do you need one? Let us explain.
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What Is a Sump Pump?
The word “sump” means pit, so a sump pump transfers water from a low-lying area (pit) to a place where it can drain safely away. You’ll often find one in a home’s basement or crawl space. In the yard, a pump that clears standing water might be called a transfer pump, but it’s basically a sump pump.
There are two kinds of sump pumps. A submersible pump spends its life underwater, while a pedestal pump stays above ground with only the water inlet filter submerged.
Submersible pumps are quieter than pedestal models, but because they’re underwater, they don’t last as long. However, noise is a major factor for most homeowners, according to seasoned plumber Danny Pen. “Pedestal pumps can last longer, but nobody installs them anymore because they’re loud and exposed.”
Ultimately, the choice depends largely on the water problem.
Why You Might Need a Sump Pump
The main reason for installing a sump pump is to keep the basement or crawl space dry. That offers related benefits, including:
- Preventing damage to the building structure;
- Controlling mold and mildew;
- Preventing electrical hazards caused by standing water.
By keeping the basement dry, a sump pump can actually increase a home’s value. Running across one in the basement during a home inspection should be reassuring rather than a cause for concern. Sure, it indicates a water problem. But it also indicates the previous owners did something about it.
A red flag would be a flooded basement without a pump to control the water. According to SANI-TRED, sixty percent of homes in America have wet basements, and many have active water problems.
Even if the basement isn’t actively flooding, a high water table is a good enough reason to install a sump pump. Excessive groundwater puts hydrostatic pressure on the basement walls and floor and can cause structural damage.
How Does a Sump Pump Work?
Most sump pumps are centrifugal, meaning they have spinning impellers. If the pump is submerged in the pit, the impeller pushes water directly into the drainage plumbing. If it’s a pedestal pump, the impeller creates suction that pulls water out of the pit and into the plumbing.
Pushing water’s easier than pulling it, so submersible pumps are generally more powerful. The pump needs a float switch to tell it when to turn on and off. There are three main types of float switches:
- A tethered float switch is a ball attached to the pump by a cord. It pivots as the water level rises, allowing a steel ball inside it to trip the switch.
- A vertical float switch rises with the water level. When it reaches a predetermined level, it turns on the pump. When the water level falls, it turns the pump off again.
- A pressure switch, the best for a small pit, monitors water pressure, which rises with the water level. It turns the pump on and off at preset values.
A plumbing pipe attached to the pump’s outlet directs water outside to a suitable drainage location. That may be a natural runoff point, a dry well or a municipal sewer, if local regulations allow. In any case, the water must drain so it doesn’t flow back to the house or onto a neighboring property.
Installing a Sump Pump
A sump pump must be installed at the lowest level of the floor. It doesn’t have to be in a pit, but digging one in the basement floor is usually the best option.
The pit is usually lined with a prefabricated plastic basin that comes with a cover. A drain tile system, a network of French drains dug into the floor and sloping toward the sump pit, may be needed to help control flooding.
Depending on the height of the water table, the plumber drops a submersible pump into the pit or installs a pedestal pump on the basement floor. The plumber then drops in the filter trap connected to the discharge pipe and sets up the float switch.
Where local regulations permit a connection between the discharge pipe and the sewer, a check valve is installed to prevent backflow into the pit. Some systems simply use a garden hose to deposit water outside. Such uncomplicated systems can sometimes be set up without a plumber, provided you follow all local laws when choosing a drainage location.
Sump Pump Maintenance
If you have a sump pump, it’s important to maintain it. “If you’ve got a sump pump and you’re not checking on it, you’re basically crossing your fingers every time it rains,” says Pen. “The problem is, sump pumps don’t usually fail while they’re running. They fail when they’re supposed to start and don’t. There are a few little things that are easy to fix, like a stuck float, a tripped outlet, or a clogged discharge pipe — and if you don’t, you might end up in two inches of water in your basement.”
Every few months or so, depending on how often the pump runs, remove the pump or pump filter from the basin and clean the filter screen. It’s also a good idea to drain the basin and clean out any debris, then fill the basin with water to ensure the float switch works.
FAQ
How often should a sump pump be serviced?
“You should test it twice a year, minimum — once before spring, once before fall,” says Pen. “If you’re in a low-lying area or your pump kicks on regularly, do it more often. And if your pump has a battery backup, replace it every few years whether it seems fine or not.”
What is the average lifespan of a sump pump?
A good-quality pump that cycles on regularly can last seven to 10 years, while a cheap one may last only three to five years. “If yours is past 6 or 7 years old, and you rely on it to keep water out, either replace it or have a backup sitting on a shelf,” advises Pen.
About the Expert
- Danny Pen is a plumber with 12 years of experience and the president at New Era Plumbing & HVAC, based in Burlington, MA.
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