[cmclaughlin]

> 3/8” is permitted by code, but not by the tables in the UPC

Can you elaborate on this please?

It takes 90 seconds for hot water to flow from my water heater to my kitchen in the winter. I’m not sure if I have 1/2 or 3/8 pex (I’d have to crawl under the house to check). I’ve been thinking of adding a small Bosch water heater under the sink or a recirculation like, but maybe I should reduce the size of the pipe too

[bombcar]

Code will have requirements like "pipe must flow X gallons/min" or something - and then a table of pipes of various materials and if they meet the requirements at a given length.

But they don't list all possible pipes, or all lengths. And the argument is that 3/8 PEX will flow to requirements and have a smaller amount of water sitting in it.