All water and sewerage systems shall be constructed and operated in accordance with all applicable State and local laws and regulations. The design of all sewerage treatment and disposal systems operated as a shared facility shall be reviewed and approved by both the Department of the Environment and the approving authority. Subsurface Disposal. There shall be an area or areas of land suitable for subsurface disposal set aside for each dwelling unit or equivalent which is equal to that specified in COMAR 26.04.03 for sewage purposes. The land so set aside may not have any structures erected upon it except that the approving authority may approve the installation of playground or athletic equipment of types which do not affect the operation or performance of the systems. This land may not be disturbed by earth moving or grading after its approval for use by the approving authority without prior authorization by the approving authority. A covering or topping such as gravel, asphalt, or concrete, which impedes the growth of vegetation, may not be placed on the land set aside for subsurface disposal. The suitability of land for wastewater disposal shall be determined in accordance with COMAR 26.04.02 and 26.04.03. The wastewater flow, by which the sizing of the disposal fields is determined, shall be calculated by adding the flows per individual unit as determined in COMAR 26.04.02. The land set aside for sewage disposal shall have enough area for the construction of the initial disposal field and two replacement fields. Collection Lines. The collection lines of any shared facility shall be guided by the design guidelines for sewerage facilities which are contained in “Design Guidelines for Sewerage Facilities” 1978 Edition (Technical Bulletin M-DHMH-EHA-S001) which is incorporated by reference. The following shall also apply: All piping, pumps, and control equipment shall be capable of withstanding the corrosive effects of anaerobic sewage. Duplex pumping facilities may not be required for individual home pumping units. Septic Tanks. All shared systems which use septic tanks shall have one tank per dwelling unit. Septic tanks shall have an access port at ground level, which is at least 24 inches in its minimum dimension, to enable the tank to be inspected and cleaned. All tanks shall be located so as to be accessible for cleaning and maintenance. Pumps. All sewerage disposal systems using septic tank effluent pumping (STEP) type collection system shall have an individual pump for each user. The pumps shall be housed in a water-tight pump pit with access to the surface of the ground. All pumps shall be located so as to be accessible for repair and replacement. The approving authority, with concurrence by the Department of the Environment, may grant exceptions to §§D—F of this regulation when, in the opinion of the approving authority, the exceptions will result in improved or equivalent operation, maintenance, or benefit to the public health, and when improved technology, determined by the approving authority to be equivalent or an improvement to that specified in §§D—F, is to be employed.