What is your ultimate goal? Staying in the home, moving out, getting the problems fixed?
A landlord has an obligation under what is called the "implied warranty of habitability" to fix serious defects in property that pose a threat to an occupant's health. You are definitely experiencing problems which could directly negatively affect your health.
Regarding your question on negligence? If your landlord knowingly rented an unsafe house to you, then you may have a civil action against him.
I would advise you to consult with a landlord/tenant attorney immediately.
You may have several claims against your landlord based on what you have described. Keep in mind, when you sue someone, you need to show "damages," meaning what your loss is or, what you hope to recover. As a tenant, you have certain rights and obligations. The landlord also has certain rights and obligations. One of his/her obligations, as the other attorney referred to, is the obligation to maintain the home in a habitible condition. While the sewage backup may or may not have been the landlord's fault, not cleaning it up and making the home livable again may be. The appliances being improperly installed also would generally be someting a landlord is responsible for, as well as the mold problem.
That being said, you have to decide what you want to do. You may be able to fix the problems and deduct the actual amount from the rent you owe as one possibility. You may put the rent into an escrow account until the landlord repairs the problems or you may terminate the lease or rental agreement under a doctrine called "constructive eviction."
Becasue I do not know your intentions, it is hard to guide you but I have attached a link to a great resource for you. It is a Landlord/Tenant Guide for Michigan and there are plenty of useful answers in there for you. Because each of the remedies I mentioned have specific elements that must be followed, please read the guide and if you need further assistance, call a local lawyer for a free consultation. I will give you two names and numbers of attorneys in your area. Your health is the greatest concern so I would definitely consider living somewhere else until the problems are resolved but you do have an obligation to notify the landlord of the situation. The longer you wait, the weaker your argument will be because the landlord may claim you accepted some of the problems. Further, you may be able to get some enforcement assistance from the local housing department or code enforcement department. Good Luck!
Attorney Crystal Carlisle: 231-726-4500
Attorney Brenda Sprader: 231-726-2500
The comments listed here do not create an attorney-client relationship. The comments are for informational purposes only and are not to be considered legal advice. This attorney is only licensed in Michigan and does not give legal advice in any other state. All comments are to be considered conversational information and you should not rely on these comments as legal advice or in place of retaining an attorney of our own. The comments here are based solely on what you have provided and therefore are general in nature and with more specific facts or details a different answer or outcome could result. The legal system is not a perfect science and this attorney does not guarantee any outcome.