Can I sue my landlord for breaking the lease due to uninhabitable conditions?
She told me that there was a problem with my septic tank and that I would have to move out because the house is not safe to live in.
A tenant often has the right to break a lease because of a dangerous condition; a landlord generally does not. Or rather: if it truly is dangerous, the landlord may have to require you to move out, BUT since it is her breach of the lease--she is failing to provide an inhabitable apartment--she is the one who will have to pay for the breach. For example, she may have to pay if not the full cost for you to live elsewhere, but pay any difference in rent if the new place costs more (including possibly paying hotel costs, if that's where you first go); she might also have to pay for other out-of-pocket costs, like moving expenses or storage costs for belongings. So yes, she can move you out of danger, but because it's her breach, you may have grounds to sue her for compensation.
What you would sue for is a breach of the lease agreement and the warranty of habitability. What do you want to sue her for? By that I mean do you want to sue her for money to move? For having to find a new place? Generally speaking when a home is uninhabitable a tenant sues the landlord for the right to break the lease and move and not to be liable for rental payments from that moment on. I would speak with a landlord tenant attorney in your area. You need something in writing that allows you to leave without being liable for the remainder of the leasehold (the rent) and you need to ask for moving expenses as well. Good luck.