Water level at Angat Dam dips below critical level

Just trying to grasp what's been said in recent articles:

1. Just how many % of the power to MM is dependent on Angat?
2. At what levels should we worry about brownouts?
3. i read another article that said "at 160m, water faucets could run dry" -- was this meant literally?
4. Another article also mentioned the possibility of rationing water in MM to 42cubic meters per household; how does this work actually? i don't think they have the means to control the consumption per household, so does it mean that, say for barangay X, we will let Y cubic meters flow out, then shut it off? E di unahan na yan?