I can't find an answer to this. I have a backyard drain to my 1929 house at the bottom of a hillside. During a storm a LOT of water drains into it. It's lined up with the basement floor drain and the inside toilet stack that runs out to the street sewer. I believe it runs to the septic system in the street, but in any modern house the gutters and yard drains would go into the gutter system. There are no holes in front of the house in the curb for gutter water like the more modern houses around me. The city does not have a separate storm/septic system. I'm pretty sure I would see all that water coming out somewhere if it was going to the curb.
I want to connect the 3" ABS sewer pipe from my tiny house to this drain. Otherwise I have to pound a big hole through the foundation to hook it up to the toilet stack. I hate punching holes in this old house. Is this a good idea or a bad idea? Is there a way to test if it's hooked up to the sewer system?