g'day dirty_james,

all our grey water goes directly to food trees and food gardens and all plant thrive plus the worms they simply love the stuff.

we make our own homemade washing detergent and use an earth friendlt dish detergent (by hand method got no time for washers), the homemade stuff gets used as hand wash surface cleaner in the washing machine pretty much anywhere we need to clean. we did drop out the essential oil in prefference to adding more eucalyptust oil just love that aroma.

deliver the water direct to the needed area do not store it for anytime all that does it makes it go smelly and deteriorates it in our books. we run it under the mulch so as not to have any evaporation.

anyhow the recipe feature on our remedies page.

len

Here is a link that might be useful: lens agrden page

Hello Dirty_James,
I don't know much about sapponins (except for quinoa)

For water purification, the only plant I can recommend from experience is cattails. They grow in almost any kind of water, and turn it into lush growth. That is what we are using in our greywater system, a four-square-meter unlined wetland on a sandy loam. Before I planted a single cattail tuber last spring, it had sealed itself up with a biomat scum and threatened to overflow. But the cattail just broke through all that, spread all through the wetland, and generally looked pretty nice. Lots better than the slimy gray hole it was last winter. Other plants in my wetland are irises, spearamint, a small willow, and a few tomatoes that must have come down the kitchen drain as seeds. Then there are the ones I just don't know what they are.
One thing I have to mention- my goal is not to hold the water, just to treat it

I don't know if any of the plants at the link below would be able to absorb saponins from the environment, but I would be interested in knowing your results if you give them a try.

Eric in Japan

Here is a link that might be useful: Saponin plants list on Wikipedia