Mosquitoes Only Need a Smidge of Water How can mosquitoes breed in such great numbers with barely any water? Well, turns out they really only need half an inch of water, and that's not much on a human scale. Twenty five hundred species of mosquitoes have been identified around the world. They prefer to lay eggs in stagnant water, letting them float along the surface. Water need not be deep, or wide, to create a mosquito nursery. Objects as small as a bottle cap and areas as narrow as the base of a potted plant work perfectly well. To keep these flying menaces away from your yard, inspect after every heavy rain. Items that cause the most trouble are old tires, whatever their use, as well as bird baths, kiddie pools and empty flowerpots. These should be emptied of standing water at least weekly. Proper maintenance of rain gutters, including leaf removal, will reduce chances of standing water forming in the first place. If all these measures only make a dent in your local mosquito population, protect yourself from bites by minimizing outdoor time (especially at dusk and dawn) and wearing repellent.