I purchased a 1930 home several years ago. About once per month there is a back up of sewage in the floor drains (one is inside and one about 2 feet apart, but outside. There is no clean out, but the previous owners (now deceased) had a hole cut in one of the main sewage lines coming from a second story bath. I clean it out and then one month later, have to do it again. I never bring anything out with the snake, which I take 30-40 feet out. The main line under the street should be only 25 feet away. If I install one way values, I assume the sewage will head up the pipes into the upstais bathrooms, or into a third floor drain, which drains the down sloping driveway before the water enters the house, and it also drains the downspouts from the roof. What is best solution to this problem without digging up the pipes?

A one way,(check) valve wouldn't stop the backups. A 1930's home has terra-cotta or cast iron sewer pipes. Either way the line is over 70 years old. Time to get a camera run through that line to see what's happening in there.
Only then will you know how to proceed. Good luck, Tom

If I install one way values, I assume the sewage will head up the pipes

That just ain't going to happen. Water flows down hill unless you somehow pump it up to a higher level

it also drains the downspouts from the roof

Sounds like you are confusing your gutter drainage with you sewer system. It would be highly unusual if your gutter system ties into the sanitary sewer system. If they are piped, they would be tied into the storm water system, something entirely different.

That just ain't going to happen. Water flows down hill unless you somehow pump it up to a higher level


Sounds like you are confusing your gutter drainage with you sewer system. It would be highly unusual if your gutter system ties into the sanitary sewer system. If they are piped, they would be tied into the storm water system, something entirely different.

I know, but the gutter system runs directly to the outside drain by the garage door. Inside the drain there is a pipe coming from the gutter system, and that in turn runs underneath the basement floor and connects with the main sewage. I thought that was extremely odd too, but I confirmed it. When there is a plug in the main line, i.e. backup, you can hear the air coming up from the gutter drain.

A one way,(check) valve wouldn't stop the backups. A 1930's home has terra-cotta or cast iron sewer pipes. Either way the line is over 70 years old. Time to get a camera run through that line to see what's happening in there.
Only then will you know how to proceed. Good luck, Tom

I assume they are cast iron pipes. When I clean out the pipes there is no dirt, roots etc coming out. Isn't the one way valve suppose to stop the backup?