(a) A regulation or compatible development standard adopted under this subchapter does not apply to:
(1) an area located in a county with a population of less than 5,000 that is adjacent to an international border;
(2) a tract of land used for a single-family residence that is located outside the boundaries of a platted subdivision;
(3) a tract of land in agricultural use;
(4) an activity or a structure or appurtenance on a tract of land in agricultural use; or
(5) any activity or a project, as that term is defined by Section 245.001, that is:
(A) occurring or in existence on the effective date of the Act adding this chapter; or
(B) receiving the benefits of or protected under Chapter 245.
(b) In this section, "agricultural use" and "agriculture" have the meanings assigned by Section 397A.051.