The only way to know for sure is to ask them! If you’re using a daycare center, they might try to tell you that state law prohibits cloth diapers in the center, and they might actually believe this, too. However, at least in Iowa, there is NO law against using cloth diapers in a daycare or group care setting. Many customers have found that chatting with their daycare provider in advance and showing them how easy it is to use cloth diapers has helped to change a reluctant care provider’s mind.
If you know that you want to use cloth diapers before you start looking for a daycare provider, include this in your interview questions. Then you can narrow your choices to just those who are willing to work with you regarding cloth diapers! (I personally would feel uneasy about leaving my child in the care of someone who was not willing work with me on this issue. What else are they going to argue about?)
You also increase your chances of having success by choosing a diaper system that makes it easy for the daycare. Prestuffed pockets or all in ones are perfect for this situation.