Safe Detergent / Soaps for Greywater use...

I recently plumbed my washing machine to greywater feed 3 trees in front of my house, one of which is a fruit tree.
I bought "Honest" detergent, supposedly plant-based and "eco-friendly", but... who trusts advertising?

Any commentary on what even these "eco-friendly" detergents can do over time to the soil in the outlet area?
Are there better commerically-available detergents out there?

I am just "filtering" by having the outlet subterrainian in an upside down put in a trench that it mulched 6" deep and leading around each tree.

Some greywater-safe detergents have been talked about in this thread.

Soap Nuts by NaturOil come from trees that produce seeds with a lot of saponins. Basically, saponins give the nuts a sudsy quality along with the ability to inhibit the growth of other organisms. If you're up for it, I found a great powerpoint online about the chemistry behind saponins.
Here's a nice video from the Survival Training School of California on saponin producing plants:

The music in the background is rather melodramatic for my taste, but nonetheless it is a nice presentation.
Plants For a Future and Mother Earth News both list plants that you can grow to make your own soap or detergents.

I have no idea what any of the "eco-friendly" detergents would do to the soil. The cleanest detergents and soaps I know of are the ones nature has made: saponin-producing plants!

Hi Andre:

Here in Phoenix we have lots of greywater harvesting. The "go to" soaps are Oasis (laundry detergent and general) and Bio-Pac.

You can read what ingredients to avoid in soaps HERE

The MOST important thing is not what the products will do to your plants, but what they do to the soil. SALTS of any kind are BAD!.
"Greywater is a fantastic way to save water, however, the products that we use to clean ourselves and our household items can be detrimental to the soil and plants that are watered with it. To minimize future soil problems, one must be a bit discerning when choosing cleaning products. Many products like bleach or other chemicals can kill plants outright. Even if a product is labeled as “biodegradable,” “natural,” or “eco-friendly” , this does not mean that is good to use for watering your yard. Due to low rainfall and high evaporation rates in San Diego many ingredients that would be perfectly fine in wetter climates can build up in our soils and cause long term problems. To ensure healthy plants and soil, keep these three ingredients to a minimum:

Salt or Sodium anything (examples include sodium lauryl sulfate, sodium hydroxide)
Chlorine
Boron or borax

For a full list of ingredients to watch out for and to learn more about greywater friendly soaps and detergents check out this site."

Taken from http://sdsustainable.org/services-and-programs/the-great-greywater-challenge/greywater-safe-soaps/

Can anybody advice, will lye or lye soap be OK in greywater?

Hello there,

Try common ivy (Hedera helix)! I find that a laundry bag (the kind one uses for delicates like bra's ) filled with leaves does the job nicely, certainly for hotter washing.
In cooler washing it doesn't quite get rid of actual stains, then it's better to make a strong "tea" of ivy and use that as a washing liquid.

Good luck!

Kaarina Kreus wrote:Can anybody advice, will lye or lye soap be OK in greywater?

we have been using lye SOAP for ages, in fact considering my family here probably for generations, and using it in the garden just fine. the lye gets tied up in the soap and isn't going to burn anything.

as for lye in the water, i'm not sure. i think it has a lot to do with how dilute it is. Soapmakers might have a better idea.

I use a mulch basin style gray water irrigation system, i.e. the washing machine gray water is directly irrigating plants.
I prefer a lye soap, or as close as I can get, for this reason. The fewer ingredients the better. Scents and dyes are obvious "No"s for this application.
The vast majority of commercially available "soaps" these days are actually detergents. Detergents can be appropriate for certain applications, but contributing to your gray water in an irrigation setting is probably not one of them.

Recently I have been using this https://rebelgreen.com/collections/all-products/products/fresh-laundry-detergent-unscented-64oz
The label shows "Saponified Organic Coconut Oil," indicating that this is in fact a type of soap (saponified = rendered into soap) made from plant fat and a type of lye. As opposed to detergent, which is made from petroleum.
There are still a few questionable ingredients, which I wouldn't feel comfortable consuming on food, but it still beats the heck out whatever is in Tide, etc.
And my gray water mulch basin is used to irrigate animal fodder crops, so any residues have to go through two other lifeforms before it gets to my table.

In my estimation, the laundry soap I linked above (or similar) is acceptable for gray water.

Since in most cases "safe" is a spectrum/gradient and not strictly yes/no, I wonder if anyone has insight or info to what extent some discharge of not ideal ingredients will affect subjected plants and soil. For example, sodium chloride (salt) which is included in lots of organic/bio labeled cleaning agents and soaps.

Lots of variables involved, particularly around drainage and volume considerations, but I'm curious if there's something like an approx yellow/orange/red threat level warning that could be flagged on some of these 'sneaky' ingredients.

Essentially, am I going to kill a nearby tree with occasional soapy runoff from an adjacent outdoor shower?

I make my own laundry soap from borax, washing soda, Castile soap, and a little bit of baking soda. It drains into a trench behind the house. It killed the rose bush but the curly dock loves it, makes huge leaves. Not sure if the stinging nettle likes it yet but it didn’t die.