Was living with a girl and she moved out before the lease was up and I could not afford to keep the rental I put up the security and lost it the every thing was in my name and her name was on the lease can I take her to court for half of the bills and sec from her being that I lost it

Yes, since her name was also on the lease you can sue her for half of everything that you had to pay. Good luck!

Did you mitigate your loss?

You have a duty to mitigate your loss within a reasonable amount of time.

And in English,

You had to try to find a new roommate. You can sue her for a month or 2, but if you can't prove you tried to find a new roommate, then you will be responsible for the rest of the costs.

That is, if she even knows the law.

Captain Forest, is it the law in Canada that there is a duty to mitigate? I'm not aware of any such requirements in the US. The landlord has a duty to mitigate loss but there is no such duty on a tenant whose co-tenant has taken off.

Yeah.

In terms of contract law, when one part breaks the contract, the other party must try to mitigate their loss.

So in this example, let's say it took HAYZAKK 3 months to find a new roommate, then his ex girlfriend would owe him 3 months rent (her share of 3 months rent).

Yes in most small claims court and most US courts, if one part to a joint lease moves out, the person who is left is expected to try and find another room mate ( unless the lease does not allow him to do that)
So if there was 6 months on the lease and the one person moves out, if the other person did not do anything to find another roommate normally they will only allow them to look for 1 or 2 months of damage.

Also they will want proof of why the deposit was lost, if it was moving out only, but if it was for leaving the apartment dirty, for leaving boxes in the apartment, for not cleaning the oven, they most likely will not give them any money for loss deposit since he did not try to get the deposit back.

So he can look at one or two months rent and 1/2 of deposit, if it was lost merely because he also moved out, But only if he tried to replace the room mate*** exception to this could be if this was a one bedroom, and the other party was "living together" in that case it may not have been possible to find a room mate.