Q1 – Does
the code specify a water supply demand for a home?
A1 – Yes
the Section P2903.6 of the IRC requires use of Tables P2903.6 and P2903.6
(1) to determine the total load (demand) on the water supply.
Q2 – If so, how is the demand determined? Examples are 2, 3,or 4 full bath home with a clothes washer connection, a
kitchen sink, and 2 hose bibs (only one operating at a time).
A2 – The
demand is calculated by adding up water supply fixtures units (Table
P2903.6 (1) for all the fixtures (or fixture groups) in the home and then
converting that total (Table P2903.6 (1)) to gallons per minute.
get educated to plumbing code so you do not purchase an undersized system that will not treat all the water all the time.