If there's another apartment above you,I'd say the trunk from your building leading to main is partially glogged. If that's the case things can get much worse(think stinky water overflowing onto floor) when trunk line glogg's even fartar. Who's responsible for plumbing,you or the apartment complex? If it's the complex's responsibility,why have they not sent someone to fix it?

Similar thing used to happen in my apartment. It was caused by another tenet flushing disposable diapers. Occurred daily for about two weeks, until mainenance identified the flusher. Our sewer pipers were in the underground garage, was common during that time to see people working on the clean outs.

I recommend contacting your landlord. Something may be in your pipe.

yes, it's a partial clog in the drain line below you. They will need to run the line.

Even those “flushable” wet wipes will kill plumbing.

Tell the building super. That's his job.

Take my advise,don't use drain cleaner. It usually doesn't work,it can damge plumbing,it is enviromentaly unfriendly and can blind you if used carelessly. Are the sinks 2 or 3 feet apart in a jack and jill or how far?

All things considered,your best option might be to hire a drain cleaning company such as Roto-Rooter or Mister Rooter that advertise's $xx.00 drain cleaning. Had you not talked about sinks backing up while you were away or at night while you slept,I might suggest renting a "sink machine" to clear the sink drain. Sink machine is just a small version of machine plumbers use for main sewer lines. To use the machine you must remove trap underneath sink,,,,and the stuff inside will gag a maggot. Guaranteed you will have that stuff on the floor and you when finished. That alone is enough for most people to pay $75 to hire it done.

"I have a reason not to (tell the building super)" sounds like a recipe for disaster. It will be a lot cheaper, easier, more effective, and prevent you from having to pay for a lot of water damage if you just do this the right way. If a problem you know about but fail to report damages the building or other people's property, YOU are liable.

Pour it in either or both because it is not going to fix the problem anyhow. Your questions were answered over a week ago and the answers haven't changed.

The reason the drain opener will not help much if there is a clog in the vertical section of the pipe is because, in order to work, it needs contact TIME on the clog. Water flows down hill, so there will be very little time in contact with the clog. Water backing up into your sinks indicates a clog in the vertical line. So, again, you can keep dumping drain cleaner and live with the risk and liability, or you can get it done correctly. Talk to the building super - unless s/he is some sort of dangerous psychopath (in which case get the building owner and law enforcement involved) there is no reason not to do so.

A slow drain is first cousin to your next stopped up and overflow. It’s a partial clog and drain cleaner is useless. Drain chemicals are actually VERY DANGEROUS YO YOU. It will burn you. It will dissolve the heck out of marble tile Heck, it can eat the gloss right off of ceramic tile. It can eat holes in galvanized plumbing and make a bad situation much worse. It’s not really safe to use and should be taken off the market.

That drain needs to be augured. You obviously aren’t up to the task. Pay a Pro. Or have the super do the job he gets paid to do.

And you better darn well be sure that your insurance covers flooding from negligence. Because it probably won’t. And your neighbor is gonna have a 59K judgement against you for ruining his apartment.

If you rent instead of own, you will be asked to leave. If you own, the super is going g to have the right to enter your apartment at will to inspect, because you were negligent in reporting issues that caused building damage.

What kind of “home professional” are you? Dare we ask? CPA? Accountant? Masseuse? All three? It certainly doesn’t involve anything design or construction related, that’s for sure.