Power backup claims in Bengaluru are mostly fiction.

After selling our big house last year, I'm looking for a manageable flat, maybe in Prestige City. Kids have moved out, don't need such a big place. I'm wondering about promised amenities. Is full flat power backup common, or just for common areas? My old house had proper backup. Also, water supply. Don't want tanker dependency. Are the water tanks actually enough for a big society? What's the real-world experience there?