Yes and No
You'll still need to have hot or at least warm water rinses to ensure total removal of soap, or at least most of it as the stuff never truly leaves fabrics.
Then there is the fact pure soaps aren't the best stain removers, and indeed can set certain types such as tannin so they are difficult to impossible to remove.
If you are going to use phosphates, yes they make great water softeners when using soap but you will have to add some to at least the first if not perhaps second rinses to ensure total soap removal.
You'll still need to have hot or at least warm water rinses to ensure total removal of soap, or at least most of it as the stuff never truly leaves fabrics.
Then there is the fact pure soaps aren't the best stain removers, and indeed can set certain types such as tannin so they are difficult to impossible to remove.
If you are going to use phosphates, yes they make great water softeners when using soap but you will have to add some to at least the first if not perhaps second rinses to ensure total soap removal.