I do not have a floor drain in my laundry room.

I have braided steel hoses, which is something. But if one of them ever lets go, that water has nowhere to go except into my floor.

I build houses for a living.

A floor drain in the laundry room is not standard. It is not on the plan, it is not in the bid, and your plumber is not going to bring it up.

It goes in when somebody asks for it. That is the entire mechanism.

If the laundry is on the second floor, you want a floor drain, or a pan that actually drains somewhere. Not a pan sitting there catching water. A pan that is piped.

Some municipalities require it for second floor laundry. Plenty do not. Code is not going to save you here, it depends entirely on where you are building.

This is where it is different from most of what I write about.

On a slab, the drain has to be there before the concrete. Not before drywall. Before the pour. And the floor has to be sloped to it, which means the plumber has to know it is coming before he roughs in and before anybody forms that slab.

Miss that window and you are not adding a floor drain. You are cutting concrete.

Here is the thing nobody tells you about floor drains.

A P-trap holds water, and that water is the only thing standing between your house and sewer gas. When it dries out there is nothing blocking it, and you get a smell.

People panic. They think something is wrong with their sewer line. Most of the time the trap just dried out.

Same thing happens in a guest shower nobody uses.

A basement drain gets water in it every once in a while. So does a garage drain.

The laundry floor drain, if it is doing its job, never gets a drop. It sits there waiting on an emergency that may never come, and the water in the trap evaporates.

The fix is simple. Pour a cup or two of water down it. Most people who have dealt with this already figured that out on their own.

The hard part is remembering.

There are two ways to keep a trap from drying out.

A trap primer ties into your water line and drips a little water into the trap so it never goes empty. It works. But it needs a water line run to it, so it is a rough in decision, and when it fails it fails quietly. Mineral buildup or a dead valve and you find out when you smell it. It is more of a commercial thing.

A waterless trap seal is a silicone one way valve that sits down in the drain. Water pushes it open, then it closes behind itself. No water line, no plumbing, and it does not care whether anybody is home.

That is the one I would use, and I would put one in a house I built.

The reason is that it does not replace the trap, it backs it up. The seal blocks the gas, and the water in the trap is still sitting there underneath as a second layer. If the seal ever wears out or something gets stuck in it, you are right back where you would have been anyway, and you pour a cup of water in it.

If you want to go put one in this weekend, here is the Green Drain waterless trap seal on Amazon. Measure your drain first, they come in a few different diameters and the wrong one will not seat.

That is an affiliate link. As an Amazon Associate I earn from qualifying purchases, and it does not cost you anything extra.

Braided steel, not rubber. Less to go wrong. That is what goes in on my jobs and it is what is on my own washer at home.

State Farm paid out close to $30 million on washing machine water damage in 2020. Their average claim was $10,200.

Does that track? It can. It depends entirely on how long the water runs and how far it gets.

If it happens on a Saturday while you are gone, and there is no floor drain, no automatic shutoff and no leak sensor, $10,200 is the floor and not the ceiling.

The drain does not stop the leak. It gives the water somewhere to go that is not your subfloor.

This one happens in planning, not at a framing walk. On a slab it has to happen before anybody forms or pours anything.

"I want a floor drain in the laundry room, and I want the floor sloped to it."

If the laundry is upstairs:

"Floor drain, or a pan that is actually piped to a drain. Not just a pan sitting there."

And while you have their attention:

"What would it cost to put an automatic water shutoff and a leak sensor in there?"

This one is item two in the plumbing section of the field guide, and there are seven more in that section alone. All of them cheap now, all of them closing before they close the walls.

Genuinely curious on this one. I suspect most of you do not have one.

If you know somebody whose plans are not final yet, forward this to them today. On a slab house this decision is gone the day the concrete truck shows up.

And if one person signs up off your link, I will send you the full cost breakdown of the first house I ever built. Every line I tracked, 2017 prices, which are going to hurt to look at. It is not for sale and it never has been.

That is it for this week.

Hit reply and tell me if you have ever had one dry out on you. I answer these myself.

Jon | Built With This