How to Identify the Bathroom Plumbing Layout in a Basement

Basement Finish Bathroom Plumbing Layout in Herriman, Utah

Hello everyone. I’m Caleb Dansie, with Dansie Design Build. Today, we are in Herriman, Utah, looking at a basement finish with a bathroom. So what I wanted to talk about was the drain piping and how you can look at what existing piping you have for drains and know if you need to have those moved. You can also see the plan for that bathroom from the beginning. 

Typically, you’ll have about three pipes sticking up out of the ground for the bathroom. One of those will probably be for the toilet, the sink, and the tub. So I’m going to talk about that and then show you the typical sizes of bathrooms and the layout. 

What Size is an Average Full Bathroom?

A typical bathroom is five feet wide. That is to allow for a standard-size tub. If we’re walking into a bathroom with the tub on the far end, which would be five feet long, we want to make sure that the framing is five feet, and if it is, then that’s probably an excellent sign that it was the intention for the area. 

One other thing is that there’ll probably be a two-inch drain pipe. This is to accommodate the P-trap for the plumbers when they do the tub drain. And 30 inches wide is the standard tub width which they have. The drain pipe is three inches, the minimum size for a toilet drain. And also, one other thing to pay attention to is the width on each side of the center line of that drain pipe for the toilet. So it must be at least 15 inches for a minimum code away from the vanity and the tub. 

Basement Bathroom Layout

The bathroom is looking pretty good with what we have laid out. It will give us enough space to have a standard 30-inch tub and then still have about 17 inches on the side of the toilet. Depending on which vanity we choose to put in will allow us to ideally have another, precisely 17 inches, so that’s centered without moving the drain pipe. The sink drain will be in the pipe where the center of the sink is, or just a couple of inches off center. And then that will let us have space to do the P-trap so it can drain.

How to Avoid Having to Move a Bathroom Drain Pipe

So, for example, suppose the vanity you chose doesn’t work, and you will need to relocate the drain but don’t want to. In this case, you can select a smaller or larger vanity. Doing this saves time and avoids the mess; if you relocate a drain, you must break out all the concrete and pour new concrete around it in the new location. 

What is a Backwater Valve Access?

The backwater valve access is often mistaken for the sink drain. The backwater valve access is for your sewer in case there’s a problem with the community sewer lines backing up and your house being lower and creating an issue. If you’re lower than the next maintenance hole, then you would technically be receiving that sewage if there was ever a clog. The backwater valve gives access to the one-way flow so that the sewer can only leave the home and never enter. So that’s what that is. So when we do the vanity, we’ll have to be leaving access for that.

Variables for Drain Relocation in a Basement Bathroom

Then, based on the actual width of the tub that we choose, whether it’s a standard 30-inch, or if we do a 32 or a 34-inch wide tub, that can push it out a little bit—and also depending on the wall framing. So if we frame it narrow or lay the two-by-fours flat instead of on the edge, that can also affect it slightly. So there are some variables we can do here to avoid having to move these if that’s a possibility. So that is how you can layout your bathroom and get an idea of the pipes.

How to Contact Dansie Design Build

If you are looking for help with your basement and are in the Salt Lake County area of Utah, you can schedule a consultation or send us a voicemail message on the right-hand side of your screen. We’d love to hear from you. Have a great day. Thanks.


Have you wondered what it costs to finish a basement in Salt Lake and Utah Counties?  Our basement finishing cost guide will give you everything you need to know.

  • Pricing for 1000 and 1500 square foot basement finishes
  • Pricing to include a bathroom, a kitchen, or open square footage
  • Pricing for Basic, Average, and Luxury Level Finishes
  • Basement walkout entrance pricing
  • Real project costs for basements we have finished
  • How to avoid the most costly mistakes while finishing a basement




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Download our FREE basement finishing cost guide. Inside we go over everything you’ll want to know.

  • Pricing calculation for any sized basement
  • Pricing to include a bathroom, a kitchen, a laundry room, or open square footage
  • Basement walkout entrance pricing
  • How to avoid the most costly mistakes while finishing a basement