Q: We’re planning a very large custom shower stall. Since we have the room, I’d like to have two separate shower mixing valves installed on opposite walls, with two rain-style shower heads. This way, I can keep one off and save water when only one shower head is needed. What are some basic considerations I should have in mind when designing a custom shower stall like this?
A: I’m happy to see you want to be water-efficient with your new custom shower stall. That leads us to the first of three basic issues to look into.
▪ Plumbing codes. Contact your local plumbing inspector and make sure your area even allows the use of two shower heads in one shower stall at the same time. Due to water restrictions, many areas of the country may have limits on shower heads and/or operation of shower heads per stall.
▪ Water supply and heating. If local codes allow you to install two separate mixing valves and shower heads, your plumber needs to size the water supply lines and water heater correctly to meet the extra demand.
▪ Drainage. While in most cases only one shower head may run, just like the water lines, you need to plan for extra drainage flow demands. The drain line needs to be sized properly for your new double shower to help avoid future double trouble.
Master contractor and plumber Ed Del Grande is the author of the book “Ed Del Grande’s House Call” and the host of TV and Internet shows. Visit eddelgrande.com or write firstname.lastname@example.org.