Any cooking water, if it doesn't have salt, goes on the garden when it has cooled down.
Water butts, the more the merrier.
My aim is to not use tap water on the garden, I have had to this week.for the first time in 5 years. But only for food plants.
Let the grass on your lawn grow. I mowed it in spring because I need to see the dog crap to.pick it up, but once summer arrives it grows seeds rather than thick leaves.
Keep showers to a minimum (and baths are for winter when there's plenty of water and it's cold enough to enjoy a hot bath).
As I said on the other thread, I was living in Cape Town 10 years ago when we were days away from water rationing and there were actual fights in supermarkets over bottled water when it opened in the morning - and the water was sold out within minutes of opening. There were still some very entitled - and rich - people who kept their sprinklers on so their gardens would be green. They just paid the fines and let everyone else suffer for their selfishness.
We used to stand in the bath and wash from a 2 litre plastic tub, when we finished washing just tipped the rest of the water in the tub over ourself as the 'shower'. We did that for 3 or 4 months... and every since I have been very conscious of water as a luxury.