Pipe Diameter?

I have experience in plumbing and know what is traditionally done when re-piping a home with copper pipe. Usually for homes around here you start with a 1" or 1 1/4" pipe and branch out to smaller diameters to ensure there is enough volume of water so that when multiple faucets are running you wont get a huge drop in pressure. The smallest diameter pipe I ever used is 1/2" with the exception of maybe a fridge or water purifier.

Anyway, I am redesigning my own kitchen and bathroom and it is a very small apartment/unit. What I was thinking about doing was relocating a water heat, most likely a tank-less water heater and supplying it with a standard 3/4" supply line. But what I was thinking about doing instead of what I normally do is running a small diameter pipe (3/8" pex or copper) to dedicated faucets to get “instant hot” water. I wont be using high volume faucets in bathroom shower or sinks so Im not worried about reduced pressure.

Question is, is this acceptable code wise or practice? Is there a good reason why I should not do this? I guess to make this inspection related, if this was found , is this something that should get called out and why?

I have this and love it I used 1/4 for return . Not to happy with the plastic hot to cold returns .


If you want more info send me email… Roy

Thanks roy, I was thinking about that but that would mean I can’t use a tankless?

I use hot water so infrequently, (a quick shower and washing hands, dishwasher uses cold water) that it makes sense to go with a tankless.