Skip to content

How to choose fixtures and design a bathroom when building an ADU

Building an ADU, like most advanced construction projects, involves many complex steps, from deciding what paint will coat the walls, to choosing what light fixtures will adorn the ceilings. But choosing bathroom fixtures is more than just an aesthetic decision, you're also selecting a layout to maximize space, choosing fixtures to reduce your water usage, and designing a relaxing space the reflects how best the space will be used.

When working with Housable to draft your construction plans, we don't specify interior finish materials meaning that we'll specify the layout of the plumbing and electric, the location and size of countertops, basins, and other utilities, but we won't tell you what specific brand to buy. Get started by either working with a design build company that can help you select products to meet your needs, or you can start shopping for things that you like and provide your builder with an interior design concept including some swatches and material ideas. 

Berkeley ADU Bathroom Shower Stall Tile Design by Housable ADU Bathroom Design by Housable in Cypress California ADU Bathroom in San Jose California Design by Housable

Working with a qualified builder will simplify this process but if you're doing the work yourself, here are some things to keep in mind. 

At a minimum you must have:

  • 30 inches of clearance for the toilet (15 inches from the center to any object on the left or right)
  • 24 inches clear in front of the toilet
  • 24 inches clear in front of the vanity
  • A shower larger than 7 square feet and room for a 30 inch circle in the center
Housable will ensure your bathroom accommodates these clearances with a layout that provides you with standard options to choose a tub or shower, vanity, and toilet. Leave an extra inch or two for clearances to prevent costly rebuilds or design changes (if you change your mind about the style of your vanity or toilet for example you want to leave enough space for a larger unit without having to rip out the walls to accommodate clearances).

Layout Math Example:

If your bathroom is 8 feet in length and you need 30 inches for the toilet you have a remaining 5 and half feet for the vanity and shower or tub. If the shower takes up another 32 inches you have a remaining 34 inches for the sink or vanity, consider choosing a sink or vanity smaller than this at 32 or 33 inches.

Other design considerations:

  • Consider who will be using the space and their mobility, older adults and disabled or alter abled individuals often require lower tubs and modified toilets. If the ADU is for an aging parent or you expect to rent it to an older individual, consider a tub with slip proof bottoms and other safety features. While average sizes and heights can accommodate most people, smaller or larger than average people may find that vanities, lights, toilets, and showerheads are either too small or too large. If you are building your ADU for a specific person like an family member, customize this space to meet their needs. If you are building it as a rental, averages will likely suffice. 
  • Consider water usage, if you live in an area with water restrictions or are conserving water for other reasons, you'll want to install low flow fixtures. Most new fixtures and utilities are built with conservation in mind but not all low flow fixtures perform in the same way. For example, some low flow shower heads reduce water flow by producing smaller steam jets, others just limit the amount of water that comes out of the fixture, both provide very different bathing experiences. 
  • Consider access to shutoff valves. When repairing plumbing, having easy access to pipes and shut off valves can save the cost of replacing walls.
  • Bathrooms are one of the most heavily used spaces in any building. Don't try to cut costs by selecting the least expensive fixtures and designs options. Look for features that will meet your needs while providing long lasting functionality. 
  • Like any space, selecting on-trend elements may make it difficult to maintain design continuity in the future. If you want to design for minimal maintenance and would like your space to have a timeless, consistent feel, look for simple fixtures with high quality craftsmanship and materials.