Water filter on Shabbat and daily

[Rute]

Dear Rabbi

We use a water filter and I have two questions on it:

1) Every morning, do I need to throw the water away in the filter - as I for instance do if any water was left in the kettle over night, or can I use it? The filter is fully closed and I wonder whether it has the same status as bottled water. Please let me know

2) Can I filter water on Shabbat? Does it come under the melacha of separating?

Thanks so much

Rute

[Moderator]

Rabbi Isaacson responds:

1.  If the pitcher is covered, then it need not be thrown out even if left in the pitcher over night.
 
2.  You can use the pitcher on Shabbos if you would drink unfiltered water (if you prefer to have it filtered). If you would not drink water straight from the tap, then it would be prohibited to filter the word on Shabbos.