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Bathroom Sink Drains

Posted by CEFreeman (My Page) on
Wed, Dec 21, 11 at 9:21

Hi all!

I purchased these Kohler 'Alterna' fixtures for my sinks in 2006. I love them and they're now discontinued:

I saw these in a restaurant and loved the way the water flowed.

ANYWAY I also bought these Kohler 'Bolero' stainless steel sinks, which I'm now thinking are too narrow (front to back):

My vanity is 96" deep and the marble is not yet fabricated. I won't do that until I'm happy with the sink issues.

I'm looking at other options, still in brushed stainless.

Getting to my concern, is there a drain hole size difference between bathroom sink fixtures and, say, bar or kitchen sink drains? I'm thinking sinks are just too big, but don't know. Unfortunately the 'Alterna' specs don't list the drain size, leading me to think there's some standard.

The wrench in the works is that on one sink, not only do I need room for these faucets, but I also have a single hole, American Standard motion sensor faucet I want to install for my cats.

So I don't need the sinks to match, given this extra little detail.

I guess I'd appreciate advice on the drain hole question and if someone has suggestions on sinks, I'm all ears.

Thanks for your help!

Follow-Up Postings:

RE: Bathroom Sink Drains

I know this is not related to your question, but I thought I should comment on the stainless sink. I have this same sink and love the look. But it is awful to keep clean. I am not the neatest of the neat freaks, but even after one use, it has spots that bother me. I find myself wiping out after each use, to keep decent looking. I thought it would be similar to my kitchen sink and not show the spots, but noooooo. I wish now I had put in a different one.

RE: Bathroom Sink Drains

Jules8, that reinforces my thought that these aren't the sinks for me. I do already own them.

I bought all my fixtures, flooring, windows, tile, etc., 6 years ago after a fire. I've been very lucky that with all these purchases, I only find I dislike a couple: the hallway lights, these sinks, and I hate my stupid windows.

I'm already online looking for something else and plan a Ferguson visit Friday.

Thanks for the input!

RE: Bathroom Sink Drains

Bathroom sinks (vanity) pipe size is 1.25 inches.
It's a small hole too, so the strainer or stopper is specifically bathroom-sink-sized.
Small = smaller than any other sink's hole (laundry tub, bar, kitchen, etc).
The size is standard in the US and Canada (and maybe everywhere else too).

Kitchen sinks have a 1.5 inch pipe. And a large size hole. A standard size.
Bar sinks always have a 1.5 inch pipe.
Bar sinks may or may not have a kitchen sink sized hole or a smaller hole.
You can call a couple manufacturers like Franke and get them to guide you to the bar sinks that have small holes.
Or... You can web search for bar sinks with small holes, but it is difficult. This is because search engines cannot figure out what to do with inches (or " ) and most manufacturers don't write inches in longhand form.

There are more details to know, if you wish. Here are a few more. The pipe that comes out of the sink is called a sink tailpiece, and this can cause some confusion because the P trap also has a pipe coming out of it called a tailpiece (or, a P-trap tailpiece, to be explicit and precise). Also, the pipe that comes out of the sink is "tubular" and that is the one key word you need to use when you go a-web-searching.

Plug these words into a search engine and see images showing pipes under a sink.
E.g. tubular continuous outlet
E.g. tubular end outlet

After the P trap, the name of the pipe TYPE changes: it is DWV and no longer tubular. Wow.


Bathroom sinks often have a pop up stopper or something.
Kitchen sinks can have this but it's seldom seen.


Bathroom strainers are good to catch hair.
Hair does not decompose. Not fast. You want to remove hair manually instead of putting it down the drain because it just clogs the drain somewhere, unless you are lucky with the geometry of your drain.

Bathroom sinks with a pop up stopper have a hair strainer inside, and one unscrews the thingie from time to time in order to remove the hair and gunk caught on the hair.


If I had your two sinks I might install the sinks and have the stone overhang a lot. A bathroom is a lot cleaner than a kitchen: it's only skin cells and hair. So underneath the overhang there is no big splash of grease and compound organic rotting stuff. Even in a kitchen, a sink overhang is not a problem, for me.

Stainless can be re-polished and this changes the surface which changes its characteristics and properties. The sinks may be repolished by any handyman. Or by you.

If you get a stainless steel shop to mold you a two tier counter top they can weld these sinks into the counter and repolish them to suit the water bead test. I have in mind a two tier counter with a little swooping curve not a discontinuity. This might be good. It might to get water to flow off the upper part of the counter if your cats let water get anywhere. I know of cats that use a drain as a urinal and then rinse it out after use. Urine left stagnant in the P trap is bad for the pipe; it needs to be rinsed out or diluted a great deal.


RE: Bathroom Sink Drains

Well, that's a wealth of information. and clear. I now understand the differences. They don't talk about bathroom sinks' drains.

I guess I need to stick to bathroom sinks. I have Emperador Dark marble coming (once I finish paying them), so even though I can see what you're talking about, it still doesn't increase the length of the bowl.

Thank goodness my kitties are neat. They just drink. Frankly, if they'd pee in the sink? I'd work with it, since I use the other side. It would be nice to have less stinky litter boxes!

I appreciate it!

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