How to turn off a reverse osmosis system ?

I have bought a house equipped with a reverse osmosis system. I'm in this house only during the week-end and I would like to know if it is possible to turn off the RO when I'm not at home (by closing the water shutoff, before the first filter of the system). It is just to save water but I wonder whether it would damage the RO membrane...
Thanks for your help.

Yes, you can shut it off by closing the feed valve before the first filter. But, if you're not home and not using water then it won't be "wasting" any water either. There's really no need to shut it off.