It's widely recommended in vegan circles to discard bean soaking water. Here's an example: > So after the beans have soaked for a while, the soaking water now contains these elements that you are trying to eliminate by soaking the beans in the first place. And this is why the bean water is discarded. So it is best to drain the water and rinse the beans thoroughly before cooking. -- https://www.vegancoach.com/why-disc…
My usual process for cooking chickpeas is:
- Soak overnight in a bowl. Throw this water out.
- Boil for several hours in new water. Save this water, and boil it down further to make aquafaba.
Not all chickpea recipes allow for this; for example, falafel is usually made with chickpeas that have been soaked but not boiled.