I have a room/bathroom addition to a home right now. Come to find out yesterday that we have 3 inch drain pipe for our toilet fixtures. Plumber states we must have 4 inch given the number of toilets. There will be a total of 5 toilets in this home. So we are no left with digging the main line out to sewer given it to is 3 inches. I understand the code for size was changed in 2006. This home was built in 1988. Any chance this home is "grandfathered in" to allow for the 3inch pipe that is already in place? Just thought I would ask given this will be a costly to our bottom line.
Thank you.

Hi R1bailey

Yeah, in my area you can only have 3 toilets on a 3" drain line, so you really are pushing the limits here, for sure!

In terms of grandfathering you in, I'd have to say that it really isn't a good idea in this case, but the final person to determine things in your area will be the plumbing inspector himself.

I'd make an appointment to see the plumbing inspector and then take a few minutes to explain your setup and see what he thinks about it. You can tell him that you will assume all responsibility and that if you have any problems then you can deal with them when they pop up. It may be helpful to offer to have the drain line videotaped to confirm the condition of the sewer line overall... helpful to you either way you look at it. Most likely, he won't approve it, but it certainly doesn't hurt to ask!

Good luck!

Mark

Call your city building department and ask them if they require/enforce that code. The house is grandfathered in most cases but not additions after code changes