(a) In determining whether a corrective action is complete, the commission shall consider the factors listed under Section 374.051(b)(3) and:
(1) individual site characteristics, including natural remediation processes;
(2) state water quality standards; and
(3) additional factors the commission considers relevant.
(b) A deviation from a state water quality standard may not result in the application of a standard that is more stringent than the applicable standard.