Someone correct me if i am wrong but 6l is all that should be flushed with new loo's as per Water regs i think. 9L if you are replacing like for like on old flushing loo
yes correct.
but 9/10 will be on the phone later complaining their new toilet don't flush very well
so i always give them a descent full flush.
thats one water reg that has to be broke. water saving my ar*e