Since I shared the recipe I use for homemade laundry detergent, I have had many questions concerning where to find Calgon water softening powder.
I purchased mine at a large grocery store in the laundry department. Since one box lasts quite a while, I have not needed to purchase for probably close two years. Maybe stores are no longer carrying it.
If you can't find water softening powder at your local store, you can purchase from Amazon.
The next question is whether the water softening powder is truly necessary if you have soft water? I can't answer that since I haven't tried the recipe without. I think the purpose of the water softening powder is to whiten laundry. If any of you have used this detergent recipe without adding water softening powder, let us know your results.