Above-ground pools are often forgotten or abandoned and are perfect hosts for organic matter and, consequently, mosquito families. (In-ground pools usually have enough chemicals to deter mosquito breeding, but beware of water accumulating on pool covers!)
Puddle dug by cars at the edge of the road. If it stays wet for 7 days, it will be productive!
Clogged eave about 7 feet off the ground, easily accessible to mosquitoes (they will fly much higher too). The obstruction at the far end (over the downpipe, which should be the low spot unless there is an installation error) needs to be cleared regularly.
Looking down this grill over a storm drain, you can see sky reflected back to you from water standing at the bottom. A beacon to egg-laying mosquitoes!
Overturned trash lids can hold water. Lids should be tightly affixed to containers at all times in order to keep out water and other common pests like rats.
Flat roof syndrome. For some reason architects or builders can’t always figure out drainage, or else the roof sags over time. Yes, mosquitoes fly pretty high. If the roof retains water for a week after eggs are laid, the roof is a breeding site!
Uncovered outdoor pile of tires. A favorite mosquito breeding site, as rain water gets in and stagnates. Read more about the problem here.