Hi, I have a question about plumbing codes in Minnesota as they relate to bathtub overflow drains.

We are renting a house built in 1960, and helping the owner, who lives out of town, make necessary repairs. It has a large sunken bathtub which was custom-built from 4" sand-pink tiles and the bottom is matching 1" mosaic tiles. (Quite the thing in 1960 I am sure.) It is actually kind of cool, and I don't want to mess with it unless I have to.

When our local inspector came to do our rental inspection, he said we needed to install an overflow drain. It has to be done by a licensed plumber, so I called one and sent him photos. He was a bit stumped about how to do it, and clearly a little nervous about drilling into the tile and whatever is behind it to get this drain installed.

Then I looked online and saw that there's some controversy about whether overflow drains actually work anyway, and apparently some codes only require them if they happen to come with the tub (which makes sense.)

So here are my questions:

1. Have any of you ever retrofit an overflow into a tub like this? How did/would you do it?
2. What's your take on the necessity of this type of drain? (As a practical matter, the thing is so big and deep that it takes a pretty long time to fill it, let alone forget to turn the water off!)
3. Do you pro plumbers think there's any chance of getting this thing grandfathered in?

I will send photos in my next post.