We have 5 bathroom vanity-style sinks in our upstairs. Looking under each sink, there is a "ridge" of sorts that is exactly where an overflow would run. The sink drains even have the hole for the overflow, just no holes in the actual sinks. All the sinks upstairs are like this, and they all drain VERY slow unless we completely unscrew and remove the drain cover (obviously lets more air in and drains fine then.) There are 5 sinks, all different areas of the house, same brand, same problem, so I know it isn't an exterior plumbing vent issue. How can I tell if they just didn't drill the holes or if this ridge is just a reinforcement for the bottom of the sink?

Here's a vanity sink with a over flow.(see image) You can learn more by clicking on; Avonite - ADA Sink > The Fabricator Network > Blog (http://www.thefabricatornetwork.com/Resources/Blog/tabid/81/articleType/ArticleView/articleId/69/Avonite-ADA-Sink.aspx)
Can you take some pictures of yours and let us look at them. Regards,Tom

Sometimes happens that wrong drain is installed ( w/o overflow hole) or plumber's putty got into the overflow channel during installation and plugged it. Do this: remove pop up plug ( stopper ), take flash light and look inside the drain. See if there is hole in the drain and on its side. Also , you may want to pour little water into the overflow ( by the rim ) and see if water goes down to the drain.

I believe overflow is required in all States. Some high design sinks and vessel sinks don't have overflow.

Hi GUYS:

If I'm reading this right, Charlie's sinks don't have any overflow holes in them... in any of them.

Sounds like the sinks have raised ridges underneath that suggest an overflow, but no hole above.

If I was Charlie I would change out 1 pop-up assembly for a vessel sink drain (see images, Charlie). If the vessel sink drain improves drainage at 1 sink it should improve drainage at the other sinks, too.

Read on Charlie...

A regular pop-up assembly will not always work real well without that overflow hole.

You may need to purchase a vessel sink drain... see images. Best bet is to purchase a flip top or a pop-up (also called mushroom or umbrella type) drain assembly. These drain assemblies mix air with water at a ratio that allows for better drainage. The grid style, even though made for vessel sinks, is not a great choice as they just don't seem to mix the air with the water the way the others mentioned above do. You will need to keep the rod from the old pop-up assembly in place to keep the hole plugged in the faucet.

Go to home depot, Lowe's or menards and purchase the better style vessel sink drain and install it on one of the sinks... betting you will be up and draining properly soon. You will also need plumber's putty...

Mark

PS: Do not confuse a regular sink pop-up assembly with a vessel sink pop up drain... totally different.

Maybe Charlie has same problem I had.

Charlie see this post.

http://Home > Home & Garden > Plumbing » Am I Dumb of What?

Got to go with Mark on this one but I have to pass the greenies around more before I can commend him