Dear All,

I was trying to find a guidance about it everywhere but didn't find or missed it.

My question is regarding is there any time limit to reuse the collected rainwater?

I did all the calculation, the 80 percentile is 12,8 mm, our project is zero lot line, and according to my caclulation we have to catch 50 m3 of rainwater.
The rainwater retention tank is 140 m3 so it's almost triple of the needed. The project owner however would like to flush toilets with the collected rainwater but agree to keep it for irrigation purposes.
But also according to my outdoor water use reduction calculation the 50 m3 is the monthy irrigation demand in the peak dry month.
So is there any time limit to reuse our if the tank capacity is enough and we use the collected rainwater for irrigation it's acceptable?

Thank you in advance.