Uninhabitable rental

[Richard T.]

Greetings all,

My first investment property has become a victim of Superstorm Sandy.The one family house is now without electric, heat, or hot water.It will likely be months until essential services are restored.My tenant believes that this excuses her from any further rent payments until the house is repaired.
How do I calculate what percentage of the monthly rent is owed?

Thank you in advance for any assistance,

RT