If you own a water well and need to replace the pump, you have to do more than just pop out the old pump and put in a new one. You have to evaluate the state of the well and your water usage, and see which type of pump would be more appropriate. You'll have to choose between jet pumps, which are very common in older wells, and submersible pumps, which have their own advantages. Jet pumps bring water to the surface and are placed at ground level; submersible pumps send water to the surface and are placed in the well water. These differences in location and method don't work for every well situation. Here's a look at what the two pumps can offer you.
Jet pumps are more suitable for shallow wells because the silt and sand of the water source's walls won't get into a pump that's above the well. Jet pumps pull up water by essentially sucking it up, and that's all you need for shallow wells. You can use submersible pumps in shallow wells, but you risk getting a lot of the silt stuck in the pump itself, which can clog the pump.
If the well is deep, though, a submersible is more appropriate. When jets suck up water, they create a vacuum in a pipe, and water rushes up to fill the vacuum. Jet pumps can't suck up water from very deep wells because the vacuum formed in the pipe can't maintain its integrity if it's followed by too much water. The water in the pipe has weight, and if the pipe is very long, the weight of the water will pull the vacuum apart. The amount of water traveling up the pipe will just be too heavy for the vacuum to keep a hold on.
But a submersible that is under the surface of the well water will push the water up—no vacuum needed. So if your well is deep, or if you're drilling a deeper well, a submersible is going to work a lot better. Plus, a deep well isn't going to have the silt problems that a shallow well would have.
Because most older wells tend to have jet pumps, it's relatively easy to replace a jet with a jet. The setup is there and just needs a bit of adjustment to fit the new jet pump model. If you have a shallow well that is producing enough water, a new jet pump is a better idea.
Switching to a submersible pump would require redoing the pump setup. This can be difficult, but if your well level has dropped and you need to drill deeper, then you can install the submersible as part of the construction on the deeper well.
Maintenance and Other Issues
While maintenance is normally a good thing—it keeps the pump working—it can be annoying to have to do too much maintenance. Submersible pumps require little maintenance, though if something happens, you do have to haul the pump all the way out of the well. Jet pumps require more maintenance but are easier to deal with because they're on the surface.
One more advantage of using a submersible pump is noise—if the pump is underwater and underground, you're not going to hear anything from it.
If you're interested in seeing models of pumps, contact a pump company like PFC Equipment, Inc and see what they offer. They can evaluate your well and let you know if a new submersible pump might be better, or if you should stick with a jet pump.