A lot is a unit of land which has an identifier provided by an assessor.  Lots are created generally via a subdivision or a main lot subdivided into two or more lots.  The division may be effective by recording an approved subdivision map or by a sale.

A legal lot is either a lot whose creation was approved generally by the County (agency) under the regulations in effect at the time of its creation or a lot which was exempt from such review at the time of its creation.

An illegal lot is one which was created without having been formally reviewed and approved by a County agency.  The conveyance of a portion of an existing lot through sale, lease, gift, or finance without proper local government approval creates an illegal lot.

Because of State laws Counties act on all illegal lots made known to it.  The step the County takes is to issue a Notice of Violation.   A lots designation as illegal is important because building permits will be denied until the violation is corrected; the sale of an illegal lot may, in some circumstances, be voided at the option of the purchaser; if the seller had actual knowledge of the lots illegality the buyer can sue the seller.

Having a parcel number does not designate a lot being legal or illegal.  The parcel identification is merely for appraisal and tax purposes. 

Title companies insure the ownership of a lot.  As to how the lot was created or how it can be used is a County action.

To make an illegal lot legal one can apply for a Conditional Certificate of Compliance.  Buyers should protect themselves prior to a purchase by contacting the Planning Division of the County where the lot is located.

Often times the legality of a lot comes into play in rural areas; generally not in an urban area but always inquire if the lot is legal (before purchase).