The greywater question is a great question and one I have never considered. From what I looked up about greywater it seems like liquid soaps are preferred. Also soaps with minimal sodium added. I do use lye which is sodium hydroxide. Though it's low on my list of ingredients(which I will post in the FAQ as well). There is about 9oz to about 4 pounds of soap. Here is a quote from one website. "If you choose a shampoo/conditioner that has sodium, but it's lower on the list or mentioned once instead of several times, chances are with it being diluted in your shower water, your plants and soil will be fine." I will post my ingredient list in the FAQ area as well as this question about greywater. I will list two websites I have looked at. I also shared this question with a goat milk soap forum to find out what other people think and some other answers. I'll keep searching, but here are two informative links.
Here is my ingredient list. It's the same five ingredients in every bar, then added is different "natural" colors, essential oil or fragrance oil.
Olive oil, coconut oil, shea butter, goat milk, betonite clay, lye, color if added, and essential oil or fragrance oil.
These are super simple ingredients that create a great bar of soap!
I want to share this link with everyone about lye in soap. It's great and it demystifies some fears about sodium hydroxide. As always, let me know if you have any questions.
Don't see the answer to your question? Ask the project creator directly.