Difference between Flush Rate and Flow Rate

Hi Ziye, thanks for your question. I see how referencing "Flow Rate" for dual flush toilets in the Water Use Reduction Additional Guidance doc (http://www.usgbc.org/Docs/Archive/General/Docs6493.pdf) might be a little confusing.

"Flush rates" are for toilets, urinals, dual flush fixtures, etc. and "flow rates"are for sinks, showerheads, etc. so just focus on that.

LEED uses a 1:2 ratio for full flush/half flush (or urinals), assuming that everyone visits the lavatory 3 times per day.

If urinals or dual flush toilets are specified, LEED assumes men use urinals (or half flush) 2 times and full flush once per day. For women, LEED assumes that if there are dual flush toilets, then women will use the half-flush twice per day and full flush once per day.

If no urinals or dual flush toilets are specified, then men (and women) would use the full flush 3 times per day. If you're inquiring in reference to the Indoor Water Use credit, just follow the instructions from Alex for calculating the weighted average for the total FTEs in the building. Let me know if this makes sense, thanks again. - Rob