Empty the water daily or every other day. Scrub algae out of the birdbath with a sponge and rinse the birdbath out with a garden hose.
Clean the birdbath weekly with one part white vinegar and four parts cold water. Pour the mixture into the birdbath and allow it to sit for 15 minutes. Scrub on the birdbath with a sponge, empty the solution and fill it with clean water.
Remove large debris from the birdbath such as feathers, leaves and twigs when you notice them. The debris will pollute the water and make it unsanitary.
Purchase a water cleaning product for birdbaths at a garden supply store. The products will contain natural enzymes that will keep the water clean.
Purchase a water wiggler for the birdbath. The wiggler will keep the surface of the water moving and keep mosquitoes away. Mosquitoes will lay eggs in still water.
Place the birdbath in a sunny location during the winter. This will keep the water warm and help prevent it from freezing. You can also heat the water in the winter with an immersion water heater.