What does "with Less Overflow" mean for a sink?

[Stephen Tashiro]

In looking at wall mount bathroom sinks on the Home Depot site, I see sinks described as "with Less Overflow Center Hole Only". What does "with Less Overflow" mean? Does such a sink have an overflow outlet or not?

[Rich Engelhardt]

Here's all you need to know... (http://lmgtfy.com/?q=What+is+a+less+overflow+sink)

;)

Not trying to be a jerk here,,,,,I just was waiting for a chance to use that ;).

& yes, Less overflow means the sink has no overflow. The current trend of bowl type sinks for instance.

[Pat Barry]

In looking at wall mount bathroom sinks on the Home Depot site, I see sinks described as "with Less Overflow Center Hole Only". What does "with Less Overflow" mean? Does such a sink have an overflow outlet or not?
Sounds like bad grammar to me.

[George Bokros]

Does it perhaps mean there is no opening to prevent sink overflow if the drain stopper is down?

[Rich Engelhardt]

Does it perhaps mean there is no opening to prevent sink overflow if the drain stopper is down?Partly - the overflow isn't built into the sink so, yes , if the water is left on and the drain is closed, it will overflow and run all over the place.

The main purpose of it however is to allow air into the drain so it can drain properly.

https://www.thespruce.com/the-purpose-of-a-sink-overflow-2718785

I had a licensed plumber tell me about it when he came out to on of our rentals to look a a slow drain. He said it's a pretty common call for him to get, right after people snake or plunge or clean the trap out on a bathroom sink.

[Jim Becker]

"No overflow" sinks are common for asthenic reasons...the sinks in our addition are that way. And Rich's mention of air flow/venting is important as that has to be considered in the plumbing design to insure proper draining. Without the venting "in the sink", an alternative vent has to be provided to avoid slow draining and that often requires some additional direct connections to the vent stack directly to the bath sink drain in the same way it's needed for kitchen sinks.

[Stephen Tashiro]

Without the venting "in the sink", an alternative vent has to be provided to avoid slow draining and that often requires some additional direct connections to the vent stack directly to the bath sink drain in the same way it's needed for kitchen sinks.

Thank you for that information! The bathroom sink I need to replace does have an overflow outlet.

[Mike Henderson]

I'm not sure I understand why a drain would drain slowly without an overflow. The drain pipe in the wall will have a vent going up the wall and through the roof (at least that's required by code around here). When you dump a bucket of water into the sink (for example) the plug of water will push air ahead of it and the air will go up the vent pretty easily. Air will follow the plug of water through the main sink drain.

So where's the congestion that will cause the drain to drain slowly? Seems that the only restriction would be the area around the drain plug. Most bathroom sinks have drain plugs that don't come out - they just raise up a small amount, making a fairly small opening for the water to get through.

There must be something I'm missing.

Mike

[Jim Becker]

Mike, the main vent for a bathroom is "beyond" the trap so when the sink doesn't have the overflow feature, it's easy to get a "bubble" that slows flow from the bowl down to the trap because the make-up air has to follow the same path as the water. I sometimes have to turn on the tap and "pulse" it to get the bowl draining if that "bubble" is hanging out. This is the exact same issue with the current generation of "safer" fuel containers that many of us use to put gas or diesel into our lawn implements...there isn't a separate vent, so the air has to come in the same place that the liquid is flowing out.

[Mike Cutler]

Jim

If it's allowed in your area, an ADV right after the weir trap might help you with that particular sink setup.
They actually make drains for, non overflow sinks, that have a flexible tube that is mounted to the underside of the vanity to facilitate venting as close to the sink drain as possible.

[Jim Becker]

Yes, I'm aware of that, Mike. It hasn't been a big enough issue to retrofit to-date, but I'm not pleased that the plumber who did the work in the addition didn't facilitate it from the start.

[Jim Koepke]

if the water is left on and the drain is closed, it will overflow and run all over the place.

Gee, that sounds like, "now with more overflow" to me.

jtk

[Dave Lehnert]

Been a long time since I replaced my bathroom sink but seem to remember an overflow was code requirement in my area.
I remember paying extra to have it added.
Maybe it was my own personal preference and not code ?????