Remove debris from the water. Combat birds' messy hygiene habits by removing feathers, droppings and miscellaneous debris from the water daily. Use a scrub brush to remove algae that results from insufficient bird bath cleaning. Do not use harsh cleaning chemicals, as the substances will harm the birds.
Replace the water frequently. Fill your bird bath with fresh water every two days, or more often if warm weather accelerates the water's evaporation rate. The splashing activities of birds may reduce the water levels too. Frequent water replacement also reduces the chance that the bird bath harbors breeding mosquitoes. This risk occurs most often during the warmer months.
Disinfect the bird bath monthly. Soak your bird bath in a diluted water-bleach solution once or twice each month. The National Audubon Society recommends nine parts water to one part bleach. Rinse the bird bath thoroughly with fresh water. Disinfecting the bird bath helps protect against bird parasites and easily transferred avian diseases.