My bathrooms share common drain line one bathroom is the hallway bathroom and the other is the master bath. The Hallway bathroom was slow draining come to find out with the lovly world of kids there was a few pennys binding the stopper constricting water flow. To be on the safe side I removed the p-trap and made sure there wasn't any other obstructions as well as the PVC that goes to the main line. Put it all back together and water is flowing out great. While cleaning up and giving the wife the OK to use sink, I noticed water is backing up from master bath sink to hallway bath sink. I tried to adjust as much as I could on the PVCs that I mucked with but I can't seem to get it right. Any advice anyone can give me would be outstanding

You have a blockage in the drain line. These baths are probably back to back right? Remove the P trap of one of the sinks and run a small hand snake to the main stack. Shouldn't be more than 15 '

You have a blockage in the drain line. These baths are probably back to back right? Remove the P trap of one of the sinks and run a small hand snake to the main stack. Shouldn't be more than 15 '

No it is just the sinks... All other plumping is fine... turn hallway sink on and drainage is fine.. run master bath and the hallway bath sink starts to fill turn water off in master bath and hallway bath drains

No it is just the sinks.... All other plumping is fine..... turn hallway sink on and drainage is fine..run master bath and the hallway bath sink starts to fill turn water off in master bath and hallway bath drains

Sorry misread what u typed out... I was reading that the bath as in tub... long days are a killer... but yes u are correct the 2 sink share the main drain line

If both lavatories are on the same drain line then remove the "J" bend from the thar of the upstream lavatory and run a snake up the into the wall, (see image). Depending upon how far the downstream lavatory is you shouldn't have to put out more then 8 feet or so of cable. Good luck, Tom

Might be a venting problem.

might be a venting problem.

Doubtful! A vent problem would slow the drainage down but his lavatories are backing up. That indicates a blockage on down the line. Cheers, Tom