Legal Question in Landlord & Tenant Law in Illinois

You have to put your case together. The first step should involve an attorney because this kind of situation can get very tricky. The next step may involve giving proper written notice to the landlord under the Illinois Residential Tenants Right to Repair Act (or local ordinance if any), wait the applicable length of time, and have the fixture repaired yourself if they do not, in which case you may be able to deduct a portion of the repair cost off the rent. If it turns out to be something that can be fixed, you may still wind up with a problem with the landlord but at least have set up your case properly because taking advantage of the Act or local ordinance is still only a defense to a later action for rent you would have to prove. If it can not be fixed, you may in fact be left with having to give another notice that you intend to vacate because the unit is not habitable without a working toilet. That could also wind up being a problem because that is called a "constructive eviction" and is only a defense you would have to prove in case the landlord later sued you for moving out and stopping rent.