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/
