Sump Pumps for the Basement

What a sump pump does, and who needs one

A sump pump is the last step in a drainage system you mostly can't see. Drain tile or gravel around the footings carries groundwater to a pit in the basement floor, called the sump. When the water in the pit rises, a switch turns the pump on. The pump pushes the water up a pipe and out of the house.

NDSU Extension calls the sump and its pump the first line of defense against water in the basement for many homeowners. It also notes that many houses have drain tile around only part of the foundation, so where the pit sits matters.

You need a basement sump pump if:

• Your house already has a pit. It needs a working pump in it.
• The basement takes on water after heavy rain or snowmelt and a plumber has recommended a sump system.

You probably don't need one if the basement has never had water and there's no pit. Start with the gutters, the downspouts and the grading.

The table above shows every sump pump in our data, sorted by the flow its maker states. The rest of this page explains each column, then the styles, then how to keep one running.

What to look at in a sump pump listing

Read the plate first. On a listing, the plate is the spec list, and these are the lines that matter.

Horsepower (HP)

Horsepower is the motor size. NDSU Extension says there's no single correct size for a house: the drainage area feeding the pit, the depth to groundwater and the depth of the basement all play into it. A 1/3 HP pump is satisfactory for most houses. The City of Edmonton's buying checklist sets the same floor.

NDSU adds that in similar conditions a 1/2 HP pump moves more water and lifts it higher than a 1/3 HP pump. Where water flows into the pit slowly, there's no advantage to the larger pump. Where flow can become rapid, the 1/2 HP pump may keep up where the 1/3 HP may not. The table covers fractional sizes and pumps past 1 HP.

"Heavy duty" shows up in a lot of listing titles. It isn't a spec. It's a mood. The HP, the flow and the housing tell you what the words don't.

Flow (GPH) and the lift it was measured at

Flow is how much water the pump moves, in gallons per hour (GPH). The trouble is that a GPH number in a title rarely says how high the pump was lifting the water at the time. Lift, also called head, is the height from the pit up to where the pipe leaves the house. Flow drops as lift rises.

NDSU says most new sump pumps come with a chart or graph, on the box or in the instructions, showing flow against height of lift. One maker's spec page for a 1/2 HP pump shows the gap: 6,000 GPH maximum capacity, and 4,140 GPH at 10 feet.

So a high capacity sump pump on paper may move far less at your lift. Compare pumps at the same height, in the same unit the makers use. We show flow as the maker lists it and never convert gallons per minute into GPH ourselves.

Max head

Max head is the height where the pump's flow runs out. Your measured lift should sit well below it. Edmonton's guide describes pump head as the distance from the sump level to where the pipe exits the home, and counts the distance the water travels too. Its checklist minimum is about 10 to 12 feet of head. Several listings in the table don't state a max head; those show a dash, and the maker's chart is the place to look.

Switch type: float switch, vertical float or tethered

The switch turns an automatic sump pump on when water rises and off when it drops. Listings name a few kinds:

• Vertical float: a float that slides up and down a rod on the side of the pump
• Tethered float: a float on a short cord that swings up with the water
• Electronic switch: a sensor with no moving float, where the listing says so

A sump pump with a vertical float stays close to its own body, which helps in a narrow pit. A tethered float needs room to swing without catching on the wall; the maker spec page above asks for a basin 14 inches or wider for its tethered model. Measure the pit's width before you shop, then check the minimum basin size in the manual.

NDSU notes one advantage of pedestal pumps: their switch is out in the open, so you can watch the ball float work.

Ken's take: the float switch is the only level in the house that gets to make decisions. He'd like that job.

Pump style

The listing names the style: submersible, pedestal, battery backup, or a primary and backup combo. The section below explains each one.

Housing material

The housing is the pump's body. Listings in the table name cast iron, stainless steel, coated steel or thermoplastic, a hard plastic. We show it as stated and don't rank by it, because none of the sources we read compares how the housings hold up. Edmonton's guide says only that a pedestal type may be better in highly corrosive areas.

Discharge size

The discharge is the outlet the pipe connects to. Most listings that state it give 1-1/2 inch or 2 inch. Edmonton's checklist calls for a 1 1/4-inch discharge line. Match the pump to your existing pipe, or fit it the way the manual shows.

Electrical listing

Some listings state a safety listing such as UL. Edmonton's guide suggests checking that a pump meets a recognized standard before you buy. We show it only when the listing names it.

Wi-Fi monitoring

A few listings state Wi-Fi monitoring, which sends alerts to your phone. That's what a smart sump pump or Wi-Fi sump pump usually means on a listing. We show the feature only when the listing names it, and we don't describe the app beyond what the listing says. The basement now has my phone number. It doesn't call to chat.

Submersible, pedestal and backup: which style fits

Most of the table is submersible. The other styles have their own pages as they open.

Submersible sump pumps

A submersible pump sits on the bottom of the pit, under water, with a sealed motor. Community Association Underwriters of America, an insurer, says submersibles are much quieter than pedestal pumps and tend to have a longer life expectancy, because the sealed motor keeps moisture and dirt out. If you want a quiet sump pump, start here. None of the listings gives a noise level in decibels. See submersible sump pumps.

Pedestal sump pumps

A pedestal pump stands in the pit with its motor up on a column, where it's meant to stay dry. CAU says pedestal pumps suit basements that need frequent drainage and are noisier. NDSU says either style works well with proper maintenance. See pedestal sump pumps.

Battery backup and water-powered backup

A sump pump battery backup is a second pump set higher in the pit, run from a rechargeable battery, that takes over when the power goes out or the primary can't keep up. A water-powered backup does the same job with the home's water pressure. CAU describes both. Edmonton's guide notes that water-powered pumps aren't as efficient as electric ones. See battery backup sump pumps and water-powered sump pumps.

Combos and kits

Some listings sell a primary pump and a backup together, and the table marks those as a combo. A sump pump kit can mean a combo, or a pump with a check valve or a basin; the listing title says what's in the box. Read it closely before you count on a part being included.

Crawl space and mini pumps

A crawl space or a shallow pit may need a smaller pump; see crawl space sump pumps. For water on a floor with no pit, NDSU describes small pumps that sit on a flat surface and pump water only 1/4 to 1/2 inch deep, often through a garden hose. Those are utility pumps, not sump pumps.

The sump pump system around the pump

A pump is one part of a sump pump system. The rest is just as important.

• Check valve. NDSU says both styles should have one on the discharge pipe so water doesn't flow back into the pit. A pump without a check valve does half its work twice.
• Discharge outlet. NDSU prefers the water to come out at least 20 feet from the house, draining away from it, not onto a neighbor's lot, into window wells or onto a septic drainfield.
• Not the floor drain. NDSU says not to pump into a basement floor drain, and especially not with a septic system. CAU says local codes prohibit sending sump water into the municipal sewer.
• The outlet. CAU says local codes require a GFCI outlet on a dedicated circuit as the pump's primary power source.
• A backup or an alarm. Edmonton's guide calls it a good idea to have one or the other, to warn you if the pump fails.

The City of Ann Arbor lists why primary pumps fail: lost power, a stuck float, a burned-out motor, a clog, a failed check valve, a blocked discharge pipe, or more water than the pump can handle. Its point is that a backup adds cost and upkeep, so weigh your own risk. Do you lose power often? Has the basement flooded before? How often is someone home to check?

Keeping a sump pump running

CAU suggests testing sump pumps at least once a year, and the maker's manual lists the specific steps for each model. Unplug the pump before you reach into the pit. NDSU's test is in the questions below.

A few habits help between tests:

• Clear debris from the bottom of the pit
• Check that the float moves freely
• Walk outside and make sure the outlet is clear
• Listen for a pump that runs and runs with nothing coming out

NDSU notes that pumps don't have filters, but the screen or small openings where water enters can plug. It also says most sump pump motors have built-in thermal protection. If a frozen pipe makes one overheat, shut it off and let it cool.

Sump pump price and where to buy

We don't show prices on this site. The "Check price" button opens the current listing on Amazon US, where the sump pump price is set and changes often. The order in the table has nothing to do with price. Brands appear as the data sorts them, with links to each brand's own page: Wayne, Basement Watchdog, Zoeller, Superior Pump, Red Lion, VEVOR, DEWALT, XtremepowerUS and more.

For a shorter list built on a stricter rule, see the best sump pumps. To size one, the sump pump sizing guide walks through it.

Read the plate first. Then go look at your pit.