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Well Pump Types Explained

Jet pump or submersible pump, and if it's a jet pump, shallow well or deep well. Here's how each type works, the depth range each one is actually built for, and where each one falls short.

The Two Main Types

According to the National Ground Water Association (NGWA), two types of pumps dominate the household well market today: jet pumps and submersible pumps. Jet pumps mount above ground, often inside a small enclosure near the wellhead. Submersible pumps are housed underwater, down inside the well itself. Which one belongs in your well depends mostly on one number, how far below the surface the water sits, plus your well's casing diameter and how much water your household needs.

How Jet Pumps Work

A jet pump sits above ground and pulls water up using suction rather than pushing it. Per NGWA, the pump's impeller, a rotor spinning at high speed, drives water through a small nozzle, creating a vacuum. That vacuum lets atmospheric pressure push water up the well and into the pipe. Because water itself is used to create that suction, jet pumps generally have to be "primed," meaning filled with water, before they'll work.

There are two versions of the jet pump, and they're built for different depths. Per NebGuide G2152 from University of Nebraska-Lincoln Extension, shallow-well jet pumps "are used when the water is less than 25 feet below the surface," while deep-well jet pumps "are used when the water is 25 to 250 feet below the surface." The difference is where the jet mechanism itself sits: in a shallow-well setup the venturi is built into the pump housing above ground, while "for deep well units, the jet is in the well, below the water level," per the same guide, connected back to the surface pump by a second pipe. NGWA similarly describes jet pumps as most often used for wells up to about 25 feet deep, noting that jet pump technology can be configured for much greater depths, though the deep-well version has real limits, covered below.

How Submersible Pumps Work

A submersible pump does the opposite of a jet pump: instead of sitting above ground and pulling water up by suction, it sits down in the well and pushes water up. Per NGWA, submersible pumps are cylindrical and fit inside the well casing, the vertical pipe that lines the borehole. The cylinder houses the pump motor along with a stack of impellers that drive water up through a "drop pipe" attached to the top of the pump; that drop pipe runs up inside the casing and connects to the distribution pipe that carries water to the house. The pump is wired to a power source with cable that runs up alongside the drop pipe and out the top of the casing.

NebGuide G2152 gives typical sizing: a submersible pump and motor are "usually about 3½ inches in diameter and 2 to 3 feet long." The guide also notes a casing requirement: "the well casing must be at least 4 inches in diameter, although some submersible pumps are available for wells 3 inches in diameter." NGWA notes that, unlike jet pumps, submersible pumps can be used at shallow depths or in much deeper wells, since they push rather than pull.

Depth Ranges at a Glance

These are the depth ranges each pump type is designed around, not a guarantee for your specific well. A driller or pump installer who knows your static water level, the well's casing diameter, and your household's water demand is the one who can confirm which pump actually fits your situation.

Pros and Cons of Each

Jet pumps. The main advantage is access: because the pump sits above ground, per NebGuide G2152, "it is easy to access for repairs." That generally makes service cheaper and faster than pulling a submersible pump. The trade-offs run the other way. A jet pump has to be primed before it will run, and per the same guide, "an air leak in the suction pipe or a water leak in the drop pipes will cause the pump to lose its prime." Jet pumps also "typically have a lower operating pressure and a lower water yield than submersible pumps," per NebGuide G2152. And because the pump lives above ground, it needs frost protection in cold climates, the same guide notes the above-ground placement is "easy to access for repairs but requires frost protection."

Submersible pumps. NGWA notes that because submersible pumps move more water with the same size motor, they are more efficient than jet pumps. They also skip the frost-protection problem entirely: per NebGuide G2152, a submersible pump "does not need frost protection since it is located below the frost line." NGWA adds that submersible pumps can be very reliable, "not requiring service for years or even decades." The downside is what happens when they do need service: both NGWA and NebGuide G2152 note that a submersible pump has to be pulled out of the well to be repaired, which typically costs more and takes longer than servicing a jet pump sitting in a surface enclosure.

Pressure Tanks and Keeping Steady Pressure

Whichever pump type is installed, it doesn't run continuously. Per NGWA, a pressure tank, usually located inside the house and typically sized between 20 and 80 gallons, stores water under pressure so the pump only cycles on when the tank's pressure drops, rather than every time a faucet opens. That buffering reduces wear on the pump significantly.

Some systems use a variable frequency drive (VFD) instead of, or alongside, a standard pressure tank setup. Per NGWA, a VFD system varies the pump motor's speed, running anywhere from half speed up to one and a half times normal speed, to hold water pressure roughly constant as demand changes, and because of that, a VFD-controlled system only needs a small pressure tank, around two to four gallons, compared to the 20-to-80-gallon tanks typical of a standard setup.

What This Means When You're Getting Quotes

Pump type isn't something you choose in isolation, it's dictated largely by how deep your well is and how wide the casing is, which is why a driller needs to know your static water level before recommending one. See our well drilling cost guide for what pump installation typically costs on top of drilling and casing, and our guide to hiring a licensed well driller for the questions worth asking before you commit to a specific pump setup.

Sourced from the National Ground Water Association's "Pumping Systems" fact sheet (NGWA, 2016) and University of Nebraska-Lincoln Extension NebGuide G2152, "Private Drinking Water Wells: The Distribution System" (Hygnstrom, Woldt, and Skipton). Depth ranges and specifications above are general guidance, not a substitute for a site-specific assessment from a licensed well or pump professional.