Here are some starting points if you want to research daycare licensing issues.
These have resources for parents, providers, employers, but it seems as though there is not much for landlords of buildings where daycare businesses are located.
If you are a landlord to a child care business, you may want to do a little extra legal research to make sure your lease (or other agreements) are suitable for the situation. You may also (please, do!) want to hire an attorney to review those agreements and otherwise advise you: How to Find a Lawyer in Oregon.
Think lead and other household toxins (see, for example, childcare provider guides here), think injuries, think legal liability!