I did mosquito treatment for a local government during college where we went to people's houses to help with mosquito prevention and untreated pools actually aren't typically a big source because they are big enough to host predators of mosquitos as well. It was always buckets or garbage cans, French drains, bird baths, unused fountains, and other small pockets of water. Definitely good advice to toss a bunch of granular mosquito bits over the fence if your neighbors have those.