Good day BiggerPockets landlords. I have an increasingly disruptive problem at a property comprised of a main 2/1 home and a stand-alone studio behind it. Turns out the studio, which is attached to a one-car garage, all runs on the same electrical box. This was not addressed in our original home inspection in October of 2013 nor have we noticed or had any complaints about the problem. A few months ago, a new tenant moved into the studio unit. The garage (which includes a washer/dryer and an exterior light illuminating the backyard of the house) is rented to the tenant in the main home. The studio tenant complained (rightfully so) that the washer/dryer and the exterior light are running off of her electrical system. We immediately said we're so sorry, didn't know and said we'll address it. We've asked for the studio electrical bills and they promised to provide them (after saying they aren't that much) but we've received nothing. So, I've been waiting while trying to estimate the usage on a bulb and a washer/dryer, which the house tenant happily provided me (her type of W/D and bulb). I can't do anything until I have the bills in question on hand and talk to the electric company. I've told the studio tenant I will offer compensation and a plan going forward for compensation. Instead of cooperating, she called code enforcement so now we have a slew of other issues, none having to do with her complaint. Typical stuff they pick on like peeling paint, a missing screen (which tenants remove all the time) and things of that nature that don't affect the tenant's life and they haven't complained about. 

The studio tenant is insisting I make the house tenant stop using her light and W/D. I don't believe I can do that as it's in violation of the house tenant's lease. I'm trying to come up with a fair solution but can't when I don't know what the costs are. The studio tenant has aggravated the situation by calling code enforcement. 

I'm looking for advice/solutions to this problem. The most extreme and expensive would be somehow wiring the W/D and light all the way across the backyard of the house into its electrical box. Is that even doable? Are there other solutions to separate the wiring that are cheaper? My original route was to estimate costs, reimburse going backward and then reduce the studio rent by the estimated usage coming from the house. Again, they won't hand over the bills so this is a no go for now (maybe they will eventually). Also, the studio tenant is generally cantankerous, very rude to the house tenant and us and seems unhappy in the unit. I've offered to let her out of the lease, refund the electric and let us all go our separate ways but she refuses that option.

Any and all ideas/advice are appreciated. Thank you in advance!