Geese like to build nests near water even though they spend most of their time on land. They are drawn to private properties for the abundance of grass, their main source of food, and easily accessible bodies of water such as rivers, streams, ponds, and even swimming pools. Unless pools are covered, geese are able to easily fly into them and splash around. The pests use pools to bathe and as breeding grounds. Wherever there are infestations of geese, there is also geese excrement. While swimming in pools, the pests defecate and contaminate the water. Though chlorine helps kill off harmful bacteria, it doesn’t completely stop the spread of diseases like salmonella, campylobacter, and E. coli. Their waste leaves hard-to-remove stains on the bottoms of pools and decks, as well. Geese in the pool will consider the area their territory and might become aggressive when people or pets get too close.