By Law you have 21 days to returned a Deposit to your tenants in full amount. If they give you for example $1200.00 this full amount needs to get back to them. No interest I had 4 properties on rent myself I'm been going thrthis process before. If either you or them give the notice to move out, yoneed to schedule and appointment with them for an unit inspection before they move out at that point if the unit needs some repairing you have to let them know all this by writing an if they move out with out fixing any damages you can deduct this from their deposit money;you have to provide them with copies of all the items fixed. By Law you can only charge for repairing $75.00 with out showing any invoice for this.

 I've never gotten interest back, but boy, that's a great question.  I sure don't know the answer, but I think if you look into landlord/tenant laws you could easily find out.  A real estate attorney would likely know too.