Miss. Code Ann. § 41-67-9: Miss. Code Ann. § 41-67-9

(1) All existing individual on-site wastewater disposal systems on July 1, 2014, shall be grandfathered in until a valid complaint is registered with a county department of health or until a property owner requests an inspection by the department.

(2) All existing individual on-site wastewater disposal systems shall be considered acceptable provided the following requirements are met:

(a) The existing individual on-site wastewater disposal system and all treated effluent is contained on the property of the generator;

(b) No evidence that any insufficiently treated effluent is leaving the property of the generator or has been seeping to the surface of the ground;

(c) Centralized wastewater treatment systems are not available;

(d) If a private water supply well is present, the well should be located at a higher elevation than the disposal system and is protected from surface contamination by a concrete slab of a thickness of at least four (4) inches extending at least two (2) feet in all directions from the well casing; and

(e) If an advanced treatment system is used, the property owner shall be required to contact an authorized representative of a certified manufacturer of the specific advanced treatment system to provide a continuous maintenance agreement or provide the property owner training to become a qualified homeowner maintenance provider.

(3) Owners of property on which an existing individual on-site wastewater disposal system does not meet the requirements of subsection (2) of this section shall be required by the department to meet Section 41-67-6 or Section 41-67-21 .