Can I break my lease without penalty because of mice and bugs?

I concur with my college above. There is a claim for a warranty of habitability issue but it must be approached appropriately and properly. Here , haste will cost you. You must have given notice, and an opportunity to cure. Once that has been done i would ,for good measure put all that has occurred in writing and contact the landlord. In these matters the use of an attorney is highly suggested. Landlords act differently when they know an attorney is involved and it makes sure that you have followed all procedures as to not be liable for an early termination and unwarranted breach of the lease.

In order to break your lease for mice droppings or other unsanitary conditions, you have to build a case against your landlord. This includes notifying the landlord of the issues, providing reasonable time for them to correct the issue, and documenting EVERYTHING along the way. Also to consider is whether such conditions actually make the premises not habitable. Is it a minor concern that is just annoying? Or does it get you and your children sick? These are things you will have to vet out with an attorney if you want to break the lease without penalty.