I'm laying out a public restroom for a small cafe that we're building. I want to have a floor drain for washing down the floor, and I've been considering installing a linear drain along the back wall (which is also the wet wall with a hung toilet, urinal, and lavatory). I got to thinking about trap primers and I know there are tailpieces that can be installed in the lavatory drain to divert some of the wastewater into the floor drain to keep its trap primed. That got me wondering: why not just divert all the water from the lavatory into the floor drain? If I do install a linear drain, it will be almost 10 feet long, so the additional water flow would help keep the drain washed down throughout the day (particularly useful in a commercial restroom where some guys tend to put as much pee on the floor as they do into the urinal).