Updated 2026-10-18
One pulls water up from the surface; the other sits in the water and pushes it. That single difference sets the depth each one can serve, how quietly and efficiently it runs, and what a service call looks like when it stops.
Best overall
Submersible, in a 4-inch well
No priming, no suction limit, no motor noise in the house. EPA names it the most common pump for deep private wells.
Best for a shallow well
Shallow-well jet, under 20 ft
Inside the tighter manufacturer limit it is the simplest system there is, and every part sits where you can reach it.
Best for serviceability
Jet pump
Seal, impeller, switch and motor come off with hand tools on the surface. Nothing has to be pulled out of the well.
A pump does not suck water up a pipe. It lowers the pressure at its inlet and the atmosphere pushes the water up to meet it. At sea level that push holds up a column of about 33.9 ft, the figure Goulds prints on its own deep-well diagram (14.7 psi of air pressure at 2.31 ft of head per psi). No real pump reaches it. Goulds rates its shallow-well jets for a practical lift of 25 ft, and that 25 includes the friction in the suction pipe, not just the vertical distance. Flotec is tighter still: with its FP2521 at sea level directly over the well, keep the total lift to 20 ft, and less when the pump is offset.
Both lose about 1 ft of lift for every 1,000 ft of elevation, so in Denver Flotec's 20 ft becomes 15. A long horizontal run eats the same allowance through friction; Flotec steps the suction pipe up a size past a 25 ft offset, and the pipe size calculator shows why bore matters on any run.
Pre-filled with an 18 ft pumping level at 1,000 ft elevation. Use the pumping level (the level while the pump runs), not the static level.
Margin to the 25 ft practical limit
6.0ft
Shallow-well jet fits
Inside the tighter manufacturer limit. Keep the suction run short and full size, because pipe friction comes out of the same allowance.
| Factor | Shallow-well jet | Deep-well or convertible jet | Submersible |
|---|---|---|---|
| Where the motor sits | Surface | Surface; jet in the well | In the well, under water |
| Pipes to the well | One suction pipe | Two (twin pipe or packer) | One drop pipe plus wire |
| Depth to water | Up to 25 ft, friction included | Over 25 ft; trade rule about 100 ft | Set in the water at depth |
| Priming | Fill before first start | Complete prime, pressure control valve | None; it starts submerged |
| Efficiency | Part of the flow recirculates to drive the jet | Same, more of it at depth | All flow goes up the pipe |
| Noise | Motor in the pump house | Same | Motor under water |
| Freeze exposure | Pump must be protected | Same | Below the frost line |
| Repairs | Hand tools at the surface | Surface, jet must be pulled | Pull pipe, wire and pump |
Flow falls off fast as lift rises. Flotec's own performance table for the 3/4 hp FP2521 at a 40 psi discharge shows it losing about two-fifths of its output between a 5 ft and a 20 ft pumping depth.
| Pumping depth | Flow at 40 psi |
|---|---|
| 5 ft | 10.2 GPM |
| 10 ft | 8.7 GPM |
| 15 ft | 7.6 GPM |
| 20 ft | 5.8 GPM |
Dug wells, driven points, cisterns and lake draws, where the pumping level stays well inside the lift limit. Goulds puts a foot valve on the end of the drop pipe in any well 2 in. or larger, kept at least 5 ft off the bottom; on a driven point a check valve at the well head lets the casing serve as the suction pipe. Suction piping runs straight or slopes up to the pump, never up and back down, because a high spot traps air and the pump will not prime.
The motor stays on the surface and drives water down one pipe to a jet set in the well, at least 5 ft below the static level per Goulds. It needs a pressure control valve to hold back pressure on the jet, or it loses prime. On a low-yield well Goulds adds a 34 ft tailpipe below the jet so the pump cannot break suction. It is the retrofit choice where a 4-inch submersible will not fit the casing.
Franklin builds its 4-inch motors for 4 in. or larger wells. A 2-wire single-phase motor (Franklin lists 1/3 to 1.5 hp) runs straight from the pressure switch with no control box. A 3-wire motor (1/3 to 5 hp) puts its capacitor start components, relay and overload in an above-ground control box, which is the part you can change without pulling the pump.
The pump type changes what is in the well. It does not change the pressure side: both a jet and a submersible start on a pressure switch and work against a pre-charged tank. Goulds ships its jet pumps with a 30/50 psi switch as standard, and both Goulds and Flotec give the same tank rule: with the tank empty of water, set the air pre-charge 2 psi below the cut-in. On a 30 psi cut-in that is 28 psi. Raise the switch and the pre-charge follows it: a 40 psi cut-in wants 38.
Check the pre-charge with a tire gauge and sparingly. Goulds notes you lose 1 to 2 psi each time you check, so a habit of checking monthly is itself a slow leak. The cut-in is also the lowest pressure the house ever sees, which is the number to feed the water pressure calculator when you want to know what the top-floor shower gets at the bottom of a cycle. For reading the switch band off a gauge, see how to check water pressure.
Two tanks, two jobs
Constant-pressure drives replace the on-off cycle with a variable-speed motor that holds a set pressure. Franklin Electric's SubDrive QuickPak package, for example, is listed for jobs up to 90 GPM and 5 hp, includes a soft start, works with a small pressure tank or the existing larger one, and pairs with a 3-phase or a single-phase 3-wire motor. Check the drive's motor list before you promise one on a 2-wire well.
A jet pump fails where you can reach it. Seal, impeller, pressure switch and motor are on the surface, and the commonest call is a lost prime: an air leak on the suction side, a foot valve that no longer holds, or a well drawn down below the jet. The price of that convenience is exposure, since both Goulds and Flotec tell you to protect the pump from freezing. A pump house that loses heat is a frozen-pipe call with a cracked casing attached.
A submersible fails where you cannot. Everything comes up together: pump, motor, the full string of drop pipe with the wire taped along it, and the water standing in that pipe. Shallow sets on plastic pipe can come out by hand with a second person; deep or heavy sets go on a pump hoist or a rig truck. The well is also open while you work, so keep the casing covered and plan for the well to be disinfected and sampled per the local health department before the household drinks from it. EPA is blunt about whose job that is: private well owners are responsible for delivering safe water to their households.
| Cost driver | Jet pump | Submersible |
|---|---|---|
| Pump unit | Horsepower; shallow or convertible | Horsepower and stages; 2-wire or 3-wire motor |
| In the well | Suction pipe, foot valve; jet assembly on deep wells | Drop pipe, submersible wire, torque arrestor, pitless |
| Depth | Sets the jet and pipe length | Sets pipe, wire length and wire size |
| Lifting gear | None | Hand pull, pump hoist or rig truck |
| Controls | Pressure switch | Switch; control box (3-wire); optional drive |
| Pressure side | Tank, switch, relief valve | Same, smaller tank possible with a drive |
There is no honest national price for a well pump job, because depth and lifting gear swing it more than the pump does. Build it from the line items above, your own hours and your crew size in the job price calculator, and price the hoist time explicitly. A pull that turns into a two-person, half-day job is the quote that loses money, which is why the shop hourly rate has to carry the truck as well as the wage.
Before you quote a pump