Sink Drain - Why holes in sides?

wrote

There should be an "overflow" slot in the sink up near the top edge. The water that goes through the overflow has to be able to get into the drain pipe, even if you have the plug in the basin, so it comes in the sides.

I'm not familiar with a vent under the sink. Usually the air is taken in at the sink overflow which is on the inside surface of the sink near the top as MasterBlaster posted, but I'm pretty sure that's what you're looking at - vent holes.

That would be the over flow. Some sinks have them some do not. Your drain (actually the part called the tailstock) should have rectangular holes in it just below the stopper to allow the water that runs into the overflow to drain out. Richard

Thanks, this sink does not have an overflow slot, so they serve no purpose on it. I guess any water that gets into these holes (gets caught in the cavity) will have to just evaporate out. This is a guest bathroom sink that is not used often

I could try filling the cavity, but I would have to take the plug assembly out again.

Those slots let the overflow water into the tailpipe. If you don't have an overflow, and the trap clogs, what's to stop water from backing up out of those holes?

When I installed a sink with no overflow (integral glass bowl and countertop) it came with it's own drain assembly that didn't have the overflow slots.

Well it sounds like you have a sink with an overflow that has a tailstock that has no provision for that. So whoever put it in that way made a mistake. If it's not used very often it's probably not a problem. It would take water trapped in there a long time to evaporate. I have kids and this would definately be a problem. Richard

replying to spudnuty, Mike wrote: I'm installing a drain and the water runs down the inside of the tailstock out the vent holes and down the outside of the tailstock onto the inside of the cabinet below. What am I doing wrong?

What "vent holes"?

Probably the place where you hook up a dishwasher. Sounds like the wrong tailpiece

But seems that would be a vent hole, not holes.... IDK, but something ain't right.

replying to Mike, Lorrie Hedges wrote: Mike, I'm faced with the same thing. I have a custom sink bowl (no overflow) and the water is running out through that slot in the drain pipe. From what I have read on this site, some come with the slot and some don't. You need to replace the drain pipe with one that does not have that extra slot/hole for the overflow. I wish I had known this before. Practice, practice, practice..... Thanks for everyone's posts.

replying to Lorrie Hedges, Hotrodky wrote: This might have saved me more trouble. My new faucet has those holes and my new sink doesn't have a drain hole. I had leaking and everything was tight. I did have a small defect under the bowl where drain pipe gets tight. That's where it was leaking. I looked at my other sinks they are bigger underneath and overflow drains into those pipes. I will look for new drain pipes without holes on sides. Other people had problems with this same vanity sink combo. They used putty and silicone.

replying to Hotrodky, Hotrodky wrote: Well I ran into another problem. I got a grid drain but it is draining slow. I'm to the point where I'm going to replace this vanity to.

Wow are you folks at HomeMoaners having all kinds of trouble. The OP had a new drain with holes, now you have a faucet with holes and a new sink that doesn't have a drain hole. Wow, are you all smoking the same stuff?

I had leaking and everything was tight.

Every sink I've had, the overflow was integrated into the sink and there was only the one drain connection at the bottom. Other types might exist, but so far it seems HomeMoaners are the only folks finding them, buying drain pipes with "holes on the sides", etc.

I will look for new drain pipes without

Probably a good idea.

Other people had problems with this same vanity sink combo.

Pros use plumbers putty, hacks use silicone.

Every slow draining sink I've seen, the problem was never the sink, it was a clogged drain, incorrect plumbing, etc. The sink just has a standard size hole in the bottom, now can it be the cause of slow draining? in the bottom

replying to trader_4, Stan wrote: I taped over the hole as couldn't find one without holes

Me too.