Hazards of cleaning out clogs with wet/dry vacuum

Question

We recently moved into a new residence with a tub that would drain very slowly, to a point where a regular shower resulted in nearly knee-high water that took ~30 minutes to make its way down the pipes. Applied all the usual troubleshooting - removed the lever drain plug, tried the baking soda & hot water method, snaked the drain as much as we could, used copious amounts of dish soap and plunged it vigorously with the overflow covered to no effect.

Finally we decided to get out our wet/dry vacuum, stick the hose on top of the drain with the cover removed, plug the tub overflow and run the unit in suction mode.

The result was instant - we pulled up nearly half a vacuum container's worth of black sludge, hair, gunk and other nastiness out of the pipes, and after ~5 minutes the tub was draining again perfectly. I was left wondering why this isn't the go-to solution for persistent clogs before the "call a plumber" step.

My question is, can I safely use this method on other blockage-related slow drains around the house (like sinks)? Does it depend on the material of the pipes used for a particular section? Would doing so be likely to damage any seals? It seems too convenient of an approach to forego, but I don't want to cause any long-term damage either (and I'm a bit surprised it's not frequently advertised as something to try). Thanks in advance!

Answer 1

To add to the other great answers, the best guess as to why the wet/dry shop vac method isn't suggested, is that most people don't "think outside the box." Also, it would not be effective for clogs much further from the drain, and the average person would not have a wet/dry shop vac. BTW, I'm wondering what you did with the black sludge and muck. (I'd like to think it was flushed down the toilet.)

Answer 2

For future seekers of knowledge on this topic.. Pro Tip: You can learn a lot from the SOUND of your ShopVac. See, generally, your bathroom plumbing will look something like this:

As such, the only clogs you're going to be able to get with a shop vac are those that lie BEFORE the drain pipe intersects with another - and that's assuming you block off the overflow valve (thats the one higher up on the bathtub).

Consider my doodlegram, here (we can presuppose your bathroom has better taste than my slapddash sketch). The rubber duckie is blocking your drain BEFORE the sink drain. As such, when you apply suction at the tub, there's nowhere else for the contents of the pipe TO go but to your vacuum. So... THOOMP!

But, after you've cleared the duckie, if that Barbie doll is ALSO stoppering you up and you apply that same suction, you'll simply start pulling air in from the sink. Your vacuum won't prove to be kenough.

That all having been said: if you apply the vacuum and once it has cleared out the water in the U-Bend, if it then starts to struggle (the sound it makes when you cover the hose with your hand), then you know A. the clog is nearby the drain, and B. sufficient vacuum force should clear it. If instead it sounds the same as it did BEFORE you applied it to the drain? Then you know it's either snaking or plumber time.

Anyway, hope this helps (there didn't seem to be any good explanations as to WHAT was happening here).

Also, full disclosure: I'm not a plumma'... I just flush a lot.

EDIT: Oh, and for gods's sakes DON'T forget to TAKE THE FILTER OUT OF YOUR SHOPVAC! THAT'S a mess-take you only make once. Expensive, too, depending on the vac!