When it comes to cleaning your cloth diapers we use detergent and not soap, here's why:
Although both soaps and detergents perform the same task, removing dirt, bacteria or poop (since we are specifically concerned about getting your diapers clean), the difference between them however are in their composition. Soaps, on the whole, are made of materials found in nature, and detergents are labeled synthetic (although some of their ingredients are natural).
So, if soap is natural why not use soap? Soap is meant to be used on generally non-porous surfaces that have no nooks and crannies to trap soil. Detergent is formulated to work on cloth, a very porous and textured material, it is also formulated to trap soil and suspend it in water where it can be washed away. Soaps form a build-up in hard water and will not rinse away easily, jeopardizing the absorption of your diapers. Detergents react less to minerals in water and do not leave this residue. Although we're a wiz at making cute cloth diapers we've left it to the scientists to explain the chemistry behind this.
We recommend to use detergent when washing & caring for our cloth diapers. We know finding a detergent that is environmentally-friendly isn’t always easy, but to maintain the longevity of your diapers, we encourage staying away from ingredients that create build-up and in turn weaken your diaper’s absorption capabilities. We also want our diapers to have every opportunity to get completely clean. What you should look for is a detergent that is Phosphate Free or low (containing trace amounts) in Phosphate, Fragrance and Dye Free and does not contain Fabric Softeners. Read Washing 101 to find the best detergent for you.