if u r real;y serious abt cancelling the contract then just go through the contract there will be some clause mentioned abt cancelling the contract

otherwise there are other reasons which u can make it to municipality and cancel the contract before maturity like if the building does nt have fire fighting and fire alarm system working then u can easily cancel u r contract and also as u told toilet is leaking this also can be one of the reason to terminate contract.

but dont regret for what u r paying u were aware of the rent before u signed. so best of luck for cancelling the contract