The following is a list of typical flow rates from taps in a two storey house with a cold water storage tank in the loft and a hot water storage tank on the first floor.
Ground Floor Kitchen: Cold tap is mains water approxiametly 20 litres/min, hot tap is 12 litres/min
First Floor Bathroom: Bath, hot and cold is 15 litres/min, basin hot and cold is 10 litres/min
These flow rates are based on 1/2″ and 3/4″ taps. A lot of the more modern taps will have reduced flow rates. Also a lot of modern taps are only suitable for high pressure systems.
Note on Combi boilers:-
A 24kw combi will give 9 litres/min at 35’C temperature rise.
A 28kw combi will give 12 litres/min at 35’C temperature rise.
A 35kw combi will give 14 litres/min at 35’C temperature rise.