(1) Subdivision lots recorded with sanitary restrictions prior to July 1, 1973, shall be reviewed in accordance with requirements set forth in this chapter. In cases where any requirements of this chapter would preclude the use for which each lot was originally intended, then the applicable requirements (including the absence thereof) in effect at the time such lot was recorded shall govern except that sanitary restrictions in no case shall be lifted from any such lot which cannot satisfy any of the following requirements:

(a) if a subsurface wastewater treatment system is utilized, soil conditions must provide for safe treatment and disposal of wastewater effluent;

(b)  the proposed water supply must comply with the requirements of this chapter; and

(c) unless a waiver is granted pursuant to ARM 17.36.601 after consultation with the local health department:

(i) if a subsurface wastewater treatment system is utilized, there must be at least four feet from the natural ground surface to a limiting layer;

(ii) the site for any subsurface wastewater treatment system may not exceed 25 percent in slope; and

(iii) no part of the lot utilized for the subsurface wastewater treatment system components addressed in Department Circular DEQ-4, Chapter 6 may be located in a 100-year floodplain.