You can search the records online, and it's FASCINATING. Start your search here. It's a little tricky to find an address - basically, you'll just search through photos of pages until you find it. Searching narrows it down to one set of 40 pages, though. And what you'll find is so worth the effort!
Our house in 1940 belonged to Mr. and Mrs. Robert Carroll, who owned the house. He was 68, she was 66. So they were born in 1872 and 1874. He had a 6th grade education, he had a 5th. He worked as a plumber, and made $520 in 1939. The value of the house was assessed at $5,000.
There weren't a lot of kids in our neighborhood at the time - a lot of older couples. The income disparities on our street were unreal - ranging from $308 to $5000 made in 1939. We were definitely a working class neighborhood at the time - electrician, printer, a few machinists, a manager at a meat shop, and the purchasing agent for the city, who made the big bucks.
Don't get started on this unless you have a few hours, but it's so exciting to look at the past! I'm about to call my grandmother and see where she was living in 1940!
If you look up your house or family, let me know what you find!!