The general rule is disclose, disclose, disclose. If you as the seller have to ask yourself, "should I disclose this to the buyer", the answer is almost always YES. It cannot hurt you to over disclose, but you can definitely be held accountable for not disclosing something that would have been important for the buyer to know.
Per Arizona statute, neither a seller nor their agent has a legal duty to disclose the following: (1) the site of a natural death, suicide, homicide, or any crime classified as a felony; (2) owned or occupied by a person exposed to HIV, or diagnosed as having AIDS or any other disease not known to be transmitted through common occupancy of real estate; or (3) located in the vicinity of a sex offender.
Material facts are facts about the property that may impact buyers decision to purchase the property.
JOSE DIAS, REALTOR
There are also some specific disclosures that a seller is required by statute to make for example, lead based paint for homes built prior to 1978 or if the property is in the vicinity of a military or public airport.
The AAR SPDS is designed to help answer what should be disclosed if known. The SPDS has six main categories: Ownership and Property, Building and Safety Information, Utilities, Environmental Information, Sewer/Wastewater Treatment, and Other Conditions and Factors.