Scarce mention of graywater here, not sure why. Generational memory loss? :-)
I saw a few comments about graywater problems and complications, which sound like they stem from lack of basic info. This ground is well covered. Perennials and graywater, if you've got any elevation at all to use, are pretty straightforward if the household greywater can be broken out of the plumbing system (that's the main challenge in most cases).
Recommended long-standing primary reference is still as far as I can see Art Ludwig's book "Create an Oasis With Greywater":
http://oasisdesign.net/greywater/createanoasis/
And his related publications (one for builders, etc.).
You can get all direct from his site (link above) or from some other non-Amazon ethical source used, such as biblio.com:
https://www.biblio.com/search.php?stage=1&pageper=20&keyisbn=art+ludwig+greywater&omit_product_types=bp,bd,ns&strip_common=1&program=1005&order=
Not legal/permittable most places, but safe as can be, and he has the research to back it up. You will have to make your own choices in your own particular situation re doing what is ecologically regenerative and water-smart, or doing what is 'legal'.
There are a few places I'm aware of where something limited, like a washing machine barrel system, can be permitted, you'd have to check with your relevant authorities (city or county usually).
You could try to change local regulations. I've seen a few institutional/municipal graywater codes and systems, including one a guy I knew helped to make happen at county level. They are all about industrial technology - pumps and filters and tanks and so on. Common sense and gravity and natural biological activity don't seem to fit the 'wastewater engineer' paradigm.
Anyhow, Ludwig's site is a gold mine for catchment/fresh/potable as well as graywater resources. Also his "first principles" for ecological design are a nice complement/other perspective on essentially same concepts as permaculture principles.
FWIW I'm in the Rogue Valley, southern Oregon, drylands climate historically and more so in recent decades.
Official "extreme drought" announced in late April this year here in Jackson county, but we've had some level of drought for decades.
I can recall one fully wet year in the last 10 (meaning the reservoirs for regional irrigation all filled by start of dry season).
Not growing a whole lot of garden this year, some early season greens and peas and strawberries, long done. Also thornless blackberries which looked good but then the intense month-long heat 'wave' (more like tsunami, just kept coming and coming) fried most before they were ready to eat. Gets too hot here in summer for delicate temperate crops (e.g. most lettuces and the like).
Watering is automated drip type system, and as soon as a section is done producing (e.g. greens bolt, peas brown out) it gets turned off.
In terms of conservation, the prior drip system here 5-6 years back or more was a typical ornamental landscaper install, drip tape or tubing all over the place watering lots of area with nothing planted in it.
I re-did the system to cover just where essential and cut the usage by about 2/3. A few ornamentals are probably dying because of that, which to me means they don't belong in this climate.
In another location nearby I have a couple mature plum trees (two types), a mature apple and two young (4-5 years) apples (each a different type), plus two kinds of grapes. These are all on timed irrigation using a simple soaker hose ring at dripline (for fruit trees) or around root base (for grapes), they get a fairly deep soak early evening but only every 4 days. Changed it to 3 days back when the heat wave just kept coming, as they were looking stressed and the plums especially are loaded with fruit that I don't want to shrivel or drop prematurely.