We had a new sink installed. (The new sink is deeper than the old sink.) The sink worked fine for the first day, but then stopped draining entirely. Our building superintendent says that the apartments above and below ours have not reported any issues and insists it must be an installation issue. Our contractor, who has already been paid, is unresponsive and insists it is not an installation issue.

We tried plunging and using a drain cleaner (similar to Drano) to no effect. A plumber snaked the pipe for 25 feet to no effect. Finally, a second plumber used a kinetic water ram. After the second plumber, the sink started working again. We were able to use it last night, but this morning it no longer drains.

What could possibly cause the sink to drain for a day but then stop entirely? Just having a theory would be useful. Our contractor, superintendent, and the plumbers are all blaming someone else and refusing to help. I want to have an idea for why so I can take a next step.

  • 3
    I would have thought that one of two plumbers would suggest this, but is the air vent clear? Does your apartment have an air vent? Also, did the contractor change the drain piping in any way behind the trap? In other words, other than removing the trap and everything up to the sink, did they cut or reroute the pipes bihind where the trap went or in to the wall?
    – noybman
    Sep 9, 2017 at 14:41
  • The plumber works for the contractor, the contractor should be hired by the superintendent. Pressure the superintendent and if he/she is uncooperative then threaten to occupy copious amount of there time by going to their boss and/or with legal action. consult your condo rules or rental contract and an attorney if need be.
    – Alaska Man
    Sep 9, 2017 at 20:06
  • noybman -- Your comment would make a good answer.
    – Jasper
    Sep 11, 2017 at 15:50

1 Answer 1


It is possible that the plumber installed a "balloon" in the drain line, in order to perform pressure testing. The plumber is supposed to remove the balloon after the pressure test is accepted. On rare occasions, the plumber forgets to remove the balloon.

The plumbers hired by my homebuilder made this mistake. It took days or weeks for the balloon in our drain line to cause the sink to stop working. During this time, we had increasing amounts of gurgling, cross-talk between sinks, and slowing down of drain times. A competent, third-party plumber we hired was unable to find the problem. The builder failed to identify the problem on their first visit(s). Both the builder and the third-party plumber guessed (incorrectly) that relocating and/or replacing a "Studor valve" might fix the symptoms. Eventually, the builder's punch-list/final clean-up guy identified the real problem, but only because the balloon was located in a cleanout whose trim work was done improperly.

Studor is a brand of air-admittance valve, or AAV. These valves are used in some jurisdictions when it would be inconvenient to vent a plumbing fixture through the building's common plumbing vent stack.

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