My Grandmother's Grey Water setup

Hello all. I just thought I would share with you a realisation that tickled me a little while back.

It's not a new idea or realisation, in general, that a lot of what we aspire to in permaculture, especially with food systems and waste avoidance/repurposing of materials, was accomplished as a matter of course by our parents' parents, simply because you had to stretch everything until it broke irreparably. But I just realised, after paying some attention to the activities of my mom's mom, who is living with my parents now, that she has been watering her garden with grey water since before I was born.

What she does is apparently similar to the British basin-in-a-sink washup, in that she collects rinse water, before and after soaping, in a larger bowl or pot in the sink. This she walks outside to a rubbermaid garbage tote that sits in the sun out by the garden, from which she waters with a watering can. I will try to get a picture of it, but it's so straightforward that anyone that washes by hand and has a garden can replicate it, even if the wash water is applied directly.

They wash with Dawn-brand dishsoap, and my grandmother is... sparing... with her applications. Everything gets squeaky clean, but I barely see any suds in the basin. I figure Dawn is the safest non-greywater-system-specific dishsoap generally available, and I know it's preferred for cleanup of living animal victims of oil spills and the like, so it's gentle on animals, but I wonder what its residues do in greywater, specifically to soil life.

Does anyone do anything similar? Are there dangers to dishsoap in greywater in this context? Does anyone have a product or recipe for dishsoap that would be better for grey water gardening?

-CK

where I used to live in the very hot desert I had my washer draining out into the cactus garden. and I never saw any problems from my reg, generic wash soup or bleach.
they did grow amazingly fast and big , my yucca bloomed every year and had babies, as well as the grass I had to keep pulling.
but then I wasn't eating those plants either.

I did this for about 20 years while I lived at an ecovillage kind of school in Ladakh, in India. My quarters were too high for the water line, so I hauled my water up from another building. I used a sink with a 15 litre container under it, and just emptied that container out into the mulch in my little garden every day or as often as needed. In winter when the garden was covered with a greenhouse, it tended to be too much water and too much nutrients, and occasionally I'd throw the water outside instead. In hot dry summer sometimes it wasn't enough water and I'd have to bring additional fresh water for the garden. Most of the time it was about enough. I was also ... sparing ... with soap, but I felt that the brief period that I used an American style liquid dish detergent instead of Indian Vim bar, my plants suffered. So I went back to the Vim bar and all was good.