Find out how to decide what kind of sump pump will best fit your needs. Learn about the most popular options and get tips on installation and maintenance.
LESLIE: Well, a sump pump  is one of those handy household appliances that you don’t need very often but when you do, it’s got to work and it has to work very well or you just might be looking at some serious below-grade flooding.
TOM: That’s right. But there are many to choose from and a variety of considerations come into play before deciding which one is best for you. With us to help sort that out is Richard Trethewey , the plumping and heating contractor from TV’s This Old House .
And Richard, this can be your best friend when the water starts to leak in but there are a lot to choose from. What are some of the options?
RICHARD: Well, the two main pumps that you’re going to see are called "submersible" and "pedestal."
RICHARD: They both work the same way. The only difference is the submersible sits down in the pit and the motor and the pump will sit underwater.
TOM: Right. So it actually is submersed under the water.
RICHARD: That’s right.
LESLIE: And it’s probably a lot quieter.
RICHARD: Right. And then the pedestal leaves the motor up above the water. And it has a long shaft with a float on it that sits down in the pit to bring the pump on when that water level rises.
TOM: I would imagine, with that long shaft and the motor above the water, that’s got to be, as Leslie said, a lot noisier.
RICHARD: Yeah, a little more noisy but you don’t really care about the noise if it’s going to make the pump go …
LESLIE: If it’s going to get the water out.
RICHARD: That’s right.
TOM: Well, that’s true.
Now, what about this sort of the real inexpensive pumps that – usually, these are the only ones left on the store shelves if you wait too long after a big storm.
RICHARD: That’s right. That’s right.
TOM: And they’re called "floor suckers."
RICHARD: Where it’s just a canister pump that has an integral sensor at the bottom, so it doesn’t have an external float. And as its name suggests, you can put it right down on the floor and it can bring that water down to within an 1/8-inch or a ¼-inch. I wouldn’t use this as my first line of defense, though; it’s a great utility pump.
TOM: Kind of good to have around but definitely doesn’t take the place of a good submersible or a pedestal pump.
RICHARD: That’s right. The other pump is pretty cool, because people definitely worry about – "My gosh, the rain is coming in. The water is coming in." And the electricity goes out.
RICHARD: And this – they have a water-powered sump pump, which is very intriguing. We showed it on This Old House a couple times. And that is that if the float comes on, water pressure will actually discharge through the pump and that water pressure will carry with it the water from the pit, so it actually works without a motor.
TOM: Oh, interesting. Right.
RICHARD: So it works without power.
TOM: So the water removes the water.
RICHARD: That’s right. So, it’s not your ideal, because you’re going to waste a little bit of water but it’s going to give you – as long as you have a water-supply system that’s not running off electricity. If you have a well pump , this won’t work.
RICHARD: But if you have city water supply, it will do a nice job.
LESLIE: Now, what about choice of materials when it comes to construction of the sump pump? Is there any benefit over ones that are made out of plastic or ones that are made out of cast iron?
RICHARD: You know, commercial pumps will almost always be cast iron; plastic pumps are cheaper but they’re not always as durable. Most pumps are going to last 5 to 10 years and cast iron might last even longer.
TOM: Now, another consideration is, really, cord length: you want to make sure that the cord is long enough to reach the power. Because very often, you don’t have power right where you need it: where that sump hole is, for example.
RICHARD: And you don’t want that extension cord sitting in a puddle in your basement, so you want to keep it in a safe place and hopefully have a grounded plug for that cord, as well.
TOM: Now, having a sump pump, obviously very important. But it’s only going to work if we have power. How do you cover yourself if the power goes out?
RICHARD: Well, they actually make a unit that has a battery backup. We did it this year on Ask This Old House and it’s really cool. The main pump plugs into a 110-volt and works just like any other submersible pump. The backup pump  has a float that’s slightly higher, so if the first pump didn’t come on, that float would activate this battery-powered pump.
RICHARD: Now, the battery is actually a deep-cycle marine battery and it’ll give you four hours of full run or if it’s run intermittently, as most pumps do, it’ll give you almost a whole day of pump.
TOM: Terrific. That’s really going to cover you, no matter what happens with the storm.
RICHARD: You hope that power comes back on within a day.
TOM: Absolutely. Richard Trethewey, the plumbing contractor from TV’s This Old House, thanks so much for stopping by The Money Pit.
RICHARD: Glad to be here.
LESLIE: Alright. You can catch the current season of This Old House and Ask This Old House on PBS. For local listings and several step-by-step videos on sump pumps, you can head on over to ThisOldHouse.com.
TOM: And This Old House and Ask This Old House are brought to you by GMC. GMC, we are professional grade.