Mich. Admin. Code R. 560.406
Rule 406. If a water well or test well has not been completed on the parcel, then water sample results or other hydrogeological information pertaining to existing wells in the vicinity of the parcel which demonstrates that the proposed on-site water supply will likely result in compliance with these rules constitutes evidence of suitability. If well record data, water sample results, and hydrogeological information are not available, or if the data indicate that unsuitable groundwater quantity or quality may exist, then the department shall either reject the development site of less than 1 acre in size or proposed subdivision under R 560.428 or issue a conditional approval with a recorded deed restriction under R 560.426.
Mich. Admin. Code R. 560.406