Backup in waste line

when i drain my upstairs bath tub i have water backup in my kitchin sink down stairs. under the house the kitchen hits the mian 1st. then the upstairs tub and shower line. note it doesnt happen with showers. parcal blockage? then the rest of the house. the line in the crawl space after the bath has i little dip in it. loose hangers need to fix. about 6 feet of 4" pvc pipe 2" dip. at the start of the mian by the kitchen line is cleanout? opened this and theres a white plastic plug? at the other end of the fitting glued/cemented in place? brake this out
and snake it? or am i padeling up the worng creek? so far cussing at it has not worked

LOL Yeah, I've noticed that cussing never helps, but I keep trying. I think your problem may be related to the dip in the line. Even if that isn't the problem, it needs to be fixed. That white plastic (PVC) plug is the clean out, but now the plot thickens. Drain snaking is really not a DIY job. The proper equipment is disaster waiting to happen in the hands of a novice. You risk serious injury to yourself, damage to the drain, and damage to the auger. I'm sure you are hoping for this to be a DIY job, but sometime us DIYers reach a point where the task outweighs our abilities and the tools needed require skills and experience we don't have. My sincere advice is to get a professional plumber who can not only clear the drain properly, but can diagnose and correct what the cause of your clog is whether it is the dip or putting things in the drain that should not have been.

thanks i'm going to fix the dip 1st. reatach the loose hangers. the clean out is at the end of a 10' stright section with the dip ie no bends to deal with. mian consurn is the white plastic cemented plug inside the cleanout. how to remove it with out damage. then when done put the loose theaded end cap back on tight. use a block and hammer to loosen then grab it out so as not to have it clog things up? or a hole saw wicth would leave a 8th" rim?

fixxed the dip in the main. filled and drianed tub. seemed slowish but no backup into kit sink. haerd grugaling at sink.

got the knockout out. easyer than i thought. can see the 4"pipe is about down to 1 1/2". checked the next pipe its clear. thinking of pushing a hose threw with a nosal on it. then turn on the hose and pull it back to clear the crud?

so the garden hose did not have enoegh pressure. so i used a pice of 1/2" pvc to loosen the crud and flushed it ou with the hose.

Chances are you just washed the mess further down the line. If so, you will have another backup probably sooner than later. This is why we recommend a professional with professional equipment that can clear the entire line clear to the street. Of course, you may have gotten off lucky.

Anytime someone's FIRST option is to "break something out", I question whether they have the knowledge to do the entire job.

that is why i asked. the white plug was geuis on someones part. put that knockout in the cleanout then if the theaded plug leaks it will be yrs bore it is found out and the waranty is over. as to the crud blocking the main down the line, that crossed my mind. so i did the work in stages getting a bit of crud loose at a time and flushing it as to all at once and checked the pipe down the line to make sure it was clear. as to use the correct tools the space was to tight to work with them. thanks for the helpfull input but maybe some on else can use it if there in the same spot and can get past my Dysgraphia.

That is a nice news. I'm happy that you've fixed your problem with the waste line.

You’re talking about a fairly rickety old drain system so the answer isn’t easy. If the original problem was a non-draining drain line the plumbing contractor may be at fault. Maybe I’m wrong, but the only way I can think of to find a stoppage in a buried line is to run a snake in thru the clean-out plug and measure how much went in before the thing stopped moving. Then you know where to dig. When the repair is done you repeat the process to make sure the line is clear.

Plumbers have been known to stuff anything from a towel to a loaf of bread into a waste line to stop “water” from dripping into the ditch where they’re working and making a nasty, muddy mess. The theory behind the bread is that it gets all soggy and washes away. The theory behind the towel is that the plumber remembers to take it out when he’s done.

Based on the crud you mentioned you might try BioClean as Terry recommended. I use the Ace Hardware equivalent when drains seem slow and it's done the job.