Yeah, reverse osmosis uses a lot of water. I would recommend just getting the fridge ones. We used to use a Brita drip thing, but the filters need to be changed often and having to refill it practically daily or a few times a day totally sucked. With the built in fridge one, I change it like once every 5 months or so and filters can be bought cheap at Amazon. Save a lot of time and is cheaper I think. Generally, your tap water is probably also safe to drink too.

Just paid a ~$46 water bill for 3k sqft house with small lawns and mostly drip irrigation for plants. In Olivenhain Municipal Water District if that makes a difference.
Maybe it’s low cause I don’t shower much?

Water bill was never that bad for us, it’s the power (gas mostly to heat) which is killer.