Why do toads get in basements?

Toads eat bugs and there are bugs outdoors in your backyard--they are good guys! You didn't say how many toads--if there are more than usual, perhaps some buildings have gone up around your yard and they have been displaced? Also, they like a more "natural" environment, so if your neighbor mows his lawn more than you do, or you have more bushes,maybe they have migratedto a safer environment. Also, toads like to live in holes or hollows--maybe your backyard has some of these too.