Water feature pumps are used in a variety of landscaping applications either to create a water feature or to help the functioning of a small, natural pond. These pumps circulate water, improving water quality through aeration and creating fountains, waterfalls, and tumbling streams. Water features are popular landscape elements and can range from small, simple ponds to elaborate combinations of features. Water feature pumps take two main forms — submersible and non-submersible. Each type of pump has an intended use, and within these two groups, sub-types exist.
All of these pumps work in the same way, using electricity to power a motor, sealed in a watertight casing, that draws water in through an intake and expels it, under pressure, from an output. They can simply move water within a pond for circulation, be fitted with a bubbler for aeration, or attached to a pipe to move water to another area, such as the head of a waterfall or tumbling stream. Submersible water feature pumps are placed directly in the water. A specialized submersible pump is used to power a fountain, which maybe connected directly to the pump or installed in another area of the feature.
Pumps that are not designed to be submerged are called external pumps. These pumps work in the same way as submersible water feature pumps but are not protected against water and must be housed in a protective enclosure. As electric devices, they are vulnerable to the elements and accidental contact with water. They serve the same function as a submersible pump but must remotely draw water from the feature through an intake pipe before pumping it to the desired destination.
Both types of pumps come in a wide range of sizes and are rated according to the amount of water they can move, usually either in gallons per hour or liters per hour. Large pumps are rated at several thousands of gallons or liters of water per hour. The size of the pump needed can be determined by estimating the total volume of water in the feature. Any pond or feature system containing live plants or fish should have a pump capable of circulating all of its water every hour or so. Pumps for fountains have ratings for suggested flow and pressure.