Read your lease carefully. If there is no language in the lease that allows the owner/realtor access under any circumstances at all, the lease provisions will govern. If there is no such language in your lease, stand your ground. I don't believe there is any state that would, by law, allow someone else access to your home whether rented or owned.
If there is not such language in your lease, inform the owner/realtor that you will regard any entry into your home (without your consent and presence) to be a criminal trespass, and that any property that might go missing during such unauthorized entry will be treated as a theft by them. Should you continue to feel pressure on this point, consult a good real estate attorney for advice.
Answered on Apr 30th, 2012 at 9:58 AM