How to Prevent Mosquito Breeding in Cisterns

Change or use the water in the cistern once a week. Be sure the container is empty and completely dry. Mosquito eggs and larvae can survive in tiny amounts of water.

Use a tight-fitting cover to prevent the mosquitoes from gaining access to the water. Add a small amount of cooking oil to cover the water surface if the lid is not tight, was left off, or if mosquitoes have found a way in.

Add the bacillus known as Bt to the water. This bacteria is harmless to animals. Follow the product label instructions for application rates.

Keep mosquito fish in the cistern if you are familiar with keeping fish as pets. These fish eat mosquito larvae, but will need care and proper water parameters. Fish are the most complicated method of mosquito prevention.