Feeding

• Feeding wildlife can attract ducks to your pool. Duck populations include a mixture of wild, tame and domesticated ducks. Even many wild ducks are used to being around humans, particularly when they have been fed by humans. Ducks lose their fear of people through such exposure, so that even if they aren't fed by a specific homeowner or at a particular site, they become less fearful of approaching areas where humans are or have been present.
  
  

Fouling and Disease

• Ducks leave behind unsightly droppings in and around swimming pools. While mallard ducks are not considered to present a public health concern and "are not significant carriers of infectious diseases transmittable to humans or domestic animals," homeowners should avoid contact with both ducks and their droppings, according to the University of Illinois Extension. Mallards rank among the species testing positive for highly pathogenic avian influenza, including H5 during the biological years 2006 thorough 2009 and H7 in 2008 and 2009, according to the USDA's Wildlife Services. Mallards may be carriers and reservoirs for these forms of influenza.
  
  

Habitat

• Yards, gardens and landscaping around pools and the protection offered by fences and other surrounding structures provide good habitat for nesting ducks as they offer shelter, some degree of isolation from predators and potential sources of food. Ducks prefer to land on water, so the USDA's Wildlife Services suggests installing a barrier such as a fence or hedge between water -- in this case, swimming pools -- and any nearby grassy areas where ducks may like to feed and rest. Additionally, Wildlife Services can trap and relocate ducks and assist with other methods to reduce or deter populations.
  
  

Deterrents

• Many deterrents prove effective at dissuading ducks from entering the area around swimming pools. In and around the pool itself, homeowners can distribute pool toys and hang decorative objects that float in the wind to frighten ducks, or utilize a pool cover to prevent ducks from entering the water. In a large yard, homeowners can combine the use of noisemaking and motion-control devices with the use of cutouts or other models of predators that hunt mallards -- such as crows, mink or foxes -- to deter ducks from entering the area.