If the home is attached to the land, it is real property, and I would argue that on a permanent foundation, attachment is accomplished. Permanent foundation is a loose term, at best, and doesn't mean a perimeter concrete or block wall anymore (see below). The de-titled thing is more about how it is taxed, but that is muddled too. A home can be delivered never having been "titled". If it is on a permanent foundation and meets all the other criteria (see below), it must be taxed as real property. But, if the title to the home and the deed to the land are in the same name(s), a call to the Assessor requesting they be taxed as real property accomplishes the same. The permanent foundation is the important distinction (mostly due to the difference in financing), but you can develop an adjustment for sales without a permanent foundation if necessary.
Edit: The "must be considered real property for tax purposes", as of recently, is being abused by the DOR. If it meets those criteria, it is being shown on public records as if it were a site-built home, and they will certainly be using site-built homes as comps, overvaluing manufactured homes at a 100% rate. Realtors don't care, even if they do have a clue, and are listing them as just another SFR, so you have to do your homework when digging through prospective comps.
Real Property Defined
70-15-101. Real property defined. Real or immovable property consists of:
(1) land;
(2) that which is affixed to land;
(3) that which is incidental or appurtenant to land;
(4) that which is immovable by law.
Manufactured Home Considered As Improvement To Real Property -- Requirements
15-1-116. Manufactured home considered as improvement to real property -- requirements. (1) A manufactured home must be considered an improvement to real property for tax purposes if:
(a) the running gear is removed;
(b) the manufactured home is attached to a permanent foundation so that it is no longer capable of being drawn over public highways and it is placed on land that is owned or being purchased by the owner of the manufactured home or, if the land is owned by another person, it is placed on the land with the permission of the landowner; and
(c) a statement of intent declaring the manufactured home as an improvement to real property is recorded with the county clerk and recorder on a form furnished by the department of justice.
(2) (a) To eliminate a manufacturer's certificate of origin properly assigned to an owner or a certificate of title of a manufactured home, an owner shall record the statement of intent, as provided in subsection (3).
(b) The statement of intent must include:
(i) the serial number of the manufactured home;
(ii) the legal description of the real property to which the manufactured home has been permanently attached;
(iii) a description of any security interests in the manufactured home;
(iv) approval from all lienholders of the intent to eliminate the certificate of origin or certificate of title; and
(v) an acknowledgment of the owner's signature.
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