No overflow - no problem?

Jun 03, 2011 14 Replies

Hi,



I have a copper sink in the bathroom and because it doesn't have an overflow, the water drains very slowly. It is not too much of a problem, because as the sink begins to fill, it drains more quickly due to gravity, but as it drains down, the rate slows down dramatically.



But my kitchen sink (as most kitchen sinks) also doesn't have an overflow, but doesn't have the same problem. How come? Is it because kitchen sinks have a larger drain?



Thanks!



Sam


Where is the vent for this sink? The overflow is not supposed to serve as a vent. If the vent is too far away you might look at adding an inside vent. Lowes has them. Is there a cabinet under the sink?

jamesgangnc wrote in news: snipped-for-privacy@hd10g2000vbb.googlegroups.com:

In the absence of a vent,wouldn't the sink drain very fast towards the end, because it is now siphoning? Perhaps more a problem with a lack of pitch of the line draining the sink, so towards the end the drain line is full, but doesn't get emptied easily. Sam, is the drain also getting to drain slowly if you keep the sink full (with some big buckets of water, or by keeping the tap wide open)? If not, that would perhaps suggest my guess is right.

The lack of an overflow doesn't cause sinks to drain more slowly. Your slow draining problem is due to something else -- possibly a partial clog somewhere in the drain line, or maybe because the sink is not close to a vent pipe.

snipped-for-privacy@hd10g2000vbb.googlegroups.com:

Not always. The pipe can be too big to develope a siphon and instead air is coming up past the water as it goes down. That reslts in slow water flow. Like what happens if you turn a gallon milk container upside down.

But I don't dsiagree that a partial clog could be to blame. Because it is a copper sink I was making the guess (perhaps wrong) that this is a hall bath and they don't get a lot of use.

Right. The (partial) clog is somewhere down the drain. Water in the sink hits the clog and backs up, like a dam, then proceeds at only the pace the miniature spillway permits.

A dose of concentrated sodium hydroxide (lye) will bust up what the miniature beavers have built.

The question of a proper vent can be answered by asking another question: Did the sink ever drain properly?

Hi, Today no sink has overflow(I think it is against code) You better make sure your plumbing vent stack is in good working order(no obstruction).

My kitchen sink is going to jail!

Most, but not all, bathroom sinks still come with an overflow port. At least that's how it is here in the U.S. An easy way to check this is to look for bathroom sinks on Home Depot and Lowes websites and look at the "Specifications" for each sink.

I don't know of any code that prohibits overflow ports in sinks, and I can't think of any reason why any such code would be written.

Yes they do. I just bought a Kohler and it and every one in the store had an overflow somewhere, usually hard to see until you look close. Not sure what you're thinkng of, but it's not an overflow for the sink. Besides, the problem here isn't the lack or presence of a sink overflow: Normally they just feed into the drain below the stopped level. There is supposed to be a vent stack for it somewhere, possibly buried in a wall or sticking out the roof or both. No, I'm not talking about air traps to stop banging.

HTH,

Twayne`

Where is the overflow on vessel sinks?

Then it's hardly an "overflow", no?

The sink overflows. ;-)

My point was that an overflow can hardly be a code requirement.

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