In order to choose the right size well pump for your well, you will need to know some key information about your well first. These details—such as well depth, your desired gallons per minute (GPM), and what you’ll be pumping water into—help narrow down your pump options to those that best fit your needs. Once you have this information, you can get a good idea of what size well pump will work for your setup. If you're unsure, a great starting point is using a well pump size calculator. You can also consult our well pump size chart for guidance. These tools can help you select the right residential water pump for your needs.
Unfortunately, there isn't a clear cut range of depths where you can say "if your well is between X and Y feet deep, you need a Z horsepower submersible well pump". The choice of deep well pumps depends on various factors. Of course, deeper wells will usually use higher horsepower pumps, but there just isn't a hard rule to follow. The reason for this is because different pump ends that push more or less gallons per minute will have different depths where they are able to perform at their best. Let's take a 200’ deep well as an example, if you wanted a water pump that will pump into a storage tank and get you 5 GPM, you would use one of our ½ HP pumps. But if you wanted to get 25 GPM out of that same well, you would need to use a 1.5 HP pump. When you want to get more GPM from a pump, you will sacrifice vertical lift in order to get a higher flow rate (given that the motor is the same HP rating). In order to get higher flow rates from the same depth well, you will have to go to a higher horsepower to be able to maintain the same lift.
You also need to take into account where the water is being pumped to. If you are pumping into a pressure tank, you need to make sure to factor that into the total lift that the pump would experience, as having to push against the back pressure of the pressure tank will add more lift. This is where a well pump pressure switch plays a crucial role in managing the system's operation. The equation you need to know is that 1 PSI = 2.31’ of lift. So if your pressure tank is a 60 PSI pressure tank, then you will have to add 138.6’ of lift onto the lift the pump has out of the well. So if we take the previous example of a 200’ deep well and pump into a pressure tank instead of a storage tank, now the pump is experiencing the 200’ out of the well, and the 138.6’ from pumping into the pressure tank, making the total lift that the pump is experiencing 338.6’. This is very important to factor in, as a pump that can do 200’ of lift may not be able to do 338.6’ of lift. Oftentimes, people will buy a well pump they think will work in their well, only to hook it up to their pressure tank and have the pump burn out as it is trying to pump water but just doesn’t have enough power.
Hopefully you found this page useful. If you still have any questions or need any clarification on what well pump is best for your specific situation, feel free to reach out to one of our pump specialists at 855-560-5670.
