Consider where the pump will be used. Submersible pumps are available in two basic designs, including well and sump varieties. Well pumps are designed to accommodate deep water applications, such as wells or ponds. Sump pumps are meant for shallow water applications, including flooded basements and small backyard ponds or fountains.
Determine the pressure requirements for your pump. The pressure of a submersible pump is also known as head or lift. It is measured as the vertical distance from the pump to the highest point of discharge. For example, if you need a pump to drain a pond that's 8 feet deep, with water draining to ground level, you'll need a pump with 8 feet of head pressure or lift.
Evaluate the flow rate. Every pump is rated for a certain flow rate, which indicates how much water the pump can move per minute or per hour. The flow rate is given in gallons per minute (GPM) or gallons per hour (GPH). Choose your flow rate based on the size of the area you need to drain, keeping in mind your required time frame for drainage.
Decide whether your pump will need to handle only liquids, or both liquids and solids. According to the Environmental Equipment and Supply Company, those who will need to drain some solid materials should look for a sewage ejector or sludge pump. Those looking to drain only liquid with no solid particles mixed in will need a simple sump pump.
Think about how your pump will be powered. Submersible pumps can be powered using AC or DC power, and some can even be hooked up to a generator. Pumps meant for DC power will have to be hard-wired, which may require the help of an electrician. AC pumps can be plugged into most standard outlets. If you plan to use a generator for your pump, look for a unit that is designed to run off your chosen generator.
Choose a pump with a durable finish. According to Hometips.com, pumps made from bronze, stainless steel or epoxy-coated iron are the most durable and long-lasting. Avoid units made from sheet metal or standard carbon or cold-rolled steel, which may rust or corrode over time.
Look for pumps with an automatic power switch option. Pumps equipped with this switch will run automatically once they are submerged, and will stop running when there is no more water to pump. This feature helps keep the motor from burning out, and is very convenient for pumps that are difficult to access.