Submersible Well Pumps: How They Work and When You Have One
A plain-English guide to submersible well pumps: how they push water up from deep in the well, their strengths, and when to call a pro.
Quick Answer
A submersible well pump is a sealed motor-and-pump unit that hangs below the water level deep inside the well casing. It pushes water up the drop pipe rather than sucking it, which is why it works well in deep wells. Pulling or replacing one is a professional job because the unit, wiring, and pipe all come out together.
How a submersible pump works
The whole unit sits underwater at the bottom of the well. A sealed electric motor drives stacked impellers (stages) that lift water into a drop pipe running up to the surface. Because the pump pushes from below instead of pulling from above, it is not limited by suction the way a shallow-well jet pump is. Power travels down a submersible cable, and a pressure switch and pressure tank at the surface tell the pump when to run.
Why they suit deep wells
- They lift water from hundreds of feet because pressure is added at the source, not drawn from the top.
- Running underwater keeps the motor cool and quiet — you usually hear nothing above ground.
- Fewer moving parts are exposed to the surface environment, so they tend to run for many years when properly sized.
- More stages (impellers) mean more lift, which installers match to well depth and yield.
What goes wrong over time
Common issues include a worn motor, a failed check valve, a torn drop-pipe fitting, sand wearing the impellers, or a problem in the submersible cable or control box. Many of these look the same from the surface — low or no water — so diagnosis usually means checking the switch, tank, and wiring first before anyone decides to pull the pump.
Pulling a pump is a professional job
If you are choosing a replacement, the pump must be matched to the manufacturer’s pump curve and to your well’s tested yield and depth — a pump that is too big can over-pump the well and draw in sand and air.
Frequently asked questions
- Can I tell from the surface whether I have a submersible pump?
- Often yes: if there is no above-ground pump housing near the pressure tank and the well is deep, the pump is likely submersible. A shallow jet pump is usually visible as a bolted unit near the tank.
- Do submersible pumps need regular maintenance?
- There is little you can do day to day since the unit is underwater. Keep the wellhead sealed and protected, watch for sand or pressure changes, and have a professional inspect the system if performance drops.
Sources & references
- Protect Your Home’s Water: Private Wells — US EPA, accessed October 29, 2026
This guide is documentary research and general information, not a laboratory analysis or professional assessment of your specific well. See our disclaimer.