We are doing a main floor bathroom reno and have switched the toilet ans shower location. Everything seemed fine until we drained the 2nd floor tub. All the water drained to the main floor new toilet and poured down to the basement. What did we do wrong? How do we fix it? All the plumbing looks fine. Today we added check valves to the new shower and sink drains. This did not help. I need some serious advice.

HI DIY...

Yeah, check valves won't be the answer. Please answer the following questions, OK?

Any chance you can take a picture of the drain/vent pipes? This would be EXTREMELY helpful.

Were all the fixtures properly vented?

What size drain pipe for the new bathroom (3" or large, right?)?

Finally, if you tested everything, any chance a TEST PLUG was left in place and needs to be removed, or perhaps the drain line is clogged?

Get back to us with the answers/pictures... see what we can think of.

Mark

Thanks a bunch. Started with the simplest answer. We had a huge nest of Q-tips in the pipe just where it was leaving the house and heading to the septic. Got to love the things kids flush.
Anjie

Thank you for the update... always nice to know things are resolved!

:)

Mark