As some of my readers know I have a rainwater collection system for watering my drought tolerant front yard in the summer and for washing laundry year-round. I had the laundry system put in in 2009, which was the year California allowed home-based rainwater collection systems. Prior to 2009, collecting and storing rainwater was against state code, despite advances in rainwater collection in other states.
Texas has published a "Texas Guide to Rainwater Harvesting" for many years. The 2nd Edition, which is available online, dates back to 1997. Rainwater collection and storage isn't new and isn't complicated.
All of my water storage is above ground, which limits the total amount to the size and room of large water barrels. The capacity of the laundry system is 2500 gallons.

The capacity of the lawn system is 4500 gallons. The photo shows two 1500 gallon barrels, but I added a third one last year.

I had the two systems connected with PVC pipe earlier this year. I could have used a long garden hose, but I preferred a more permanent connection. I now have about 4000 combined gallons remaining from last year's rain that I can use for either my front yard or laundry as needed. This should be enough to last through the end of October, when I hope we will start getting rain again.
I'm growing dirt in the back yard. I couldn't see any reason to waste water on grass back there. I gave away most of the sprinkler heads to someone on FreeCycle. The drought tolerant plants in my front yard don't require much water and I don't use much for laundry. Obviously a large family with young children would require a lot more loads of laundry each week than I need.
The drought is so bad this year I felt the need to cut back on my one last waste of water. It takes 40 seconds for hot water to reach my bathroom sink from the water heater in the garage. So in cold weather I would run the water until it warmed up.
With a 2.2 gpm aerator on my faucet, this wasted almost one-and-a-half gallons of water each time I needed warm water to wash with. So last week I had a small, 2.5 gal., point-of-use water heater installed in my bathroom to keep that 1.5 gallons from going down the drain.

Putting a "water saving aerator" on my sink wouldn't save water under these circumstances. It would just take longer for the hot water to reach the sink. I see no point for me to use water saving aerators. There's already a water saving feature on every sink. It's called a faucet! If I want to limit the flow of water I can just turn down the faucet.
Of course this depends on whether members of your household keep their usage down. Low flow aerators force conservation on all members of the household. So they can be useful to curb water wasters if you have family members who leave water running. I save a lot more water outside where most water is wasted on traditional lawns and gardens.
All new homes should be built with rainwater capture and grey water recycling. If the systems are built in, you would be able to put the storage underground and not in large barrels that take up a lot of room and are not particularly attractive. A 1500 sq. ft. roof can capture 1,000 gallons of water per inch of rain. This isn't new technology. The Romans and Egyptians used it thousands of years ago. It makes sense to do it now too.