A common recipe for birdbath cleaning is one part bleach to 10 parts water, yet there are effective environmentally friendly alternatives. The right birdbath location and a routine for regular maintenance makes cleaning the easily stained concrete less of a chore. A neglected birdbath can harm birds by spreading disease. Keep three basic household products on hand for bird-safe concrete birdbath care that's also friendlier to the environment.
Empty the birdbath once a week and scrub the inside surface with a stiff-bristled brush and mild soap. This keeps the concrete clean if the bath is well-maintained with daily water changes.
Pour at least 1 cup of undiluted white vinegar into the birdbath once or twice a month for algae removal if buildup occurs. Add more vinegar if needed to cover the bath's bottom. Clean the concrete with vinegar more often in the summer, if necessary.
Scrub the concrete with a wire brush in two or more directions to loosen algae, mildew and soiling. Rinse the birdbath thoroughly with a hose.
Mix 1/4 cup of borax in two cups of hot water, stirring with a spoon. Pour the mixture into the birdbath. Borax kills mold and mildew and helps remove stubborn stains. Scrub the mixture into the concrete with a wire brush.
Rinse the birdbath at least twice to remove all the residue. Refill it. Limit the water depth to 2 to 3 inches. Birds prefer low water and will avoid a birdbath when the water is too deep.