Outdoor water fountains make a charming addition to any garden, but they also require additional maintenance. Expect to do a major cleaning of your outdoor fountain monthly. But you can cut down on the required maintenance by locating your pump away from sources of debris like trees, which may drop leaves into it.
Use distilled water in your fountain to avoid mineral deposits building up on the fountain and in the pump.
Add an algae-blocking product to the water to help prevent algae growth.
Check the fountain every day or two, and immediately after windy or stormy events, for debris like leaves and dirt. Turn off the fountain and inspect the pump too. Remove any debris you find.
Perform more in-depth maintenance at least once a month if you notice such debris as dirt, dust, leaves or soil in the fountain. Turn the fountain off, drain the water and wipe the reservoir clean with a damp cloth.
Remove the pump from the fountain and wipe it clean with a wet cloth. Pull the cover off the pump and remove the magnetic impeller, checking for any debris that may have accumulated. Then replace the impeller and cover and reassemble the fountain.
Use a very diluted solution of bleach---one part bleach to 10 parts or more of water---or white vinegar to remove any algae growth you notice during routine cleaning. Then fill the fountain with water again and turn it back on. Never let the water sit stagnant if you can at all avoid it.