What It Is
A submersible well pump is a sealed electric motor and pump assembly that operates fully submerged inside a well casing, typically 100 to 400 feet underground. Unlike a jet pump that pulls water from above, a submersible pump pushes water upward from below, making it more efficient for deep wells. The sealed motor is cooled by the surrounding groundwater and requires no priming.
What It Does
The submersible pump is the heart of a deep well water system. It draws groundwater from the aquifer surrounding the bottom of the well and pushes it up through the drop pipe to the surface, into the pressure tank, and through the home's plumbing. Because the pump is below the water it is pumping, it creates positive pressure pushing upward - far more efficient than pulling water up from above ground, which faces suction limits related to atmospheric pressure.
Modern residential submersible pumps are highly reliable, often running for 15 years or more without issues. Because they are located deep in the well, they are protected from freezing and most environmental damage, but when they do fail, retrieving them for repair or replacement requires pulling hundreds of feet of drop pipe and electrical cable - specialized work that requires the right tools and knowledge.
Where It Is Located
The pump is installed at the bottom of the well casing, suspended by the drop pipe (usually polyethylene or galvanized steel) and held up by the weight of the water column above it and the wellhead sanitary seal at the top. The electrical cable runs alongside the drop pipe and connects to the pressure switch at the surface. The only surface evidence of the pump's location is the well head - a capped pipe or pitless adapter at grade - and the electrical conduit running to the pressure switch and tank.
How It Works
A submersible pump contains a multi-stage centrifugal pump assembly driven by a sealed electric motor below it. When the pressure switch calls for the pump to run, 240V electricity travels down the drop cable to the motor. The motor spins the impeller stages at high speed, drawing water in through a screen at the bottom and accelerating it upward through each stage until it exits into the drop pipe at significant pressure. Each pump stage adds pressure - deep wells require more stages to overcome the height of the water column above the pump.
Common Problems or Signs of Failure
- Complete loss of water with no tripped breaker - pump motor may have failed
- Significantly reduced flow rate - impellers may be worn or the well yield has dropped
- Sandy or gritty water - pump is at or below the water table, drawing sediment from the aquifer bottom
- Pump runs but pressure does not build - drop pipe may have developed a leak or the pump is worn
- Unusually high electric bills - a failing pump draws more current as it struggles
Can a Homeowner Check It?
- Check the circuit breaker - a tripped breaker is the most common and easiest cause to check first
- Check the pressure gauge - if it reads zero and the pump does not start, note whether the breaker is tripped or the switch contacts are open
- Inspect the well head for any signs of damage, flooding, or contamination that might have affected the system
- The pump itself is underground and cannot be checked without specialized equipment
When to Call a Plumber
Any pump issue beyond a tripped breaker requires a well service professional. Pulling a submersible pump involves hundreds of feet of drop pipe and requires a pump puller or pitless adapter wrench - tools most homeowners do not have. A plumber with well pump experience can pull the pump, test it, and determine whether repair or replacement is the better option. If the pump is older — often in the range of 12 to 15 years or more — and failing, replacement is often the more practical choice, though a plumber can assess the specific situation.
Related Plumbing Problems
Related Plumbing Terms
Related Gray's Services
Have a Plumbing Question? We Can Help.
Gray's Precision Plumbing serves Northeast Ohio. Call or text for a straight answer on what's wrong and how to fix it.
Call 440-723-8850 Send a Message