This section does not apply to: in Montgomery County: an apartment house with fewer than five dwelling units; or a water supply or sewage collection and disposal system constructed: to serve only a single building or group of buildings serving as a single farm unit or as a single commercial or industrial establishment; by the county, an instrumentality of the county, or the City of Rockville; or by a municipality, if the municipality owned and operated the system on June 1, 1965; and in Prince George’s County, a water supply or sewage collection and disposal system: constructed to serve only a single family residence or a single building; or owned and operated by a municipality on January 1, 1959. This subsection does not apply to Calvert Manor. Subject to subsection (c) of this section, a person shall obtain a permit from the Commission before the person may construct, alter, extend, or operate a water supply or sewage collection and disposal system outside the sanitary district in Montgomery County or Prince George’s County. The Commission may not issue a permit under subsection (b) of this section until the Commission approves: complete plans and specifications for the construction, alteration, extension, or operation of the water supply or sewage collection and disposal system; and any other information that the Commission requires. The Commission shall: during construction, inspect all projects for which the permit was issued; and require the construction to conform to the approved plans and specifications. The Commission may charge a reasonable permit fee not exceeding 6% of the estimated construction cost for a project described in this section. A person holding a permit under subsection (b) of this section shall submit to the Commission: any material change in the plans and specifications; and a statement of the reasons for the change. The Commission shall approve and issue a permit for a material change before the person may include the change in the actual construction. A water supply or sewage collection and disposal system, including oxidation ponds and sewage lagoons, for which a permit is required under this section shall be installed, maintained, and operated under regulations that the Commission adopts. The Commission shall: inspect the operations of any water supply or sewage collection and disposal system authorized under this section; require the owners or operators of the system to maintain and operate the system in compliance with the Commission’s reasonable requirements and with regard to public health, safety, and comfort; set and collect from the owners or operators of the system a reasonable fee for the supervision and inspection of the system; and if the owner or operator fails or refuses to correct, maintain, or operate the system in compliance with the Commission’s requirements: make the correction or take over the operation of the system for any period necessary; and collect the costs for the correction or operation from the owner or operator. The Commission: shall adjust its inspection fees accordingly if a municipality in Montgomery County or Prince George’s County: owns or operates a water supply or sewage collection and disposal system; performs or has performed bacteriological and chemical analyses on the system by qualified personnel, as approved by the Department of the Environment and the Commission; and files with the Commission a monthly report of the analyses showing that satisfactory operating conditions exist in the system; and is not required to duplicate an analysis. If a water or sewage treatment facility is constructed under a Commission permit and operates subject to inspection by the Department of the Environment, the Commission is not required to duplicate the operational inspection functions that the Department of the Environment conducts. The Commission may eliminate or reduce its operation and inspection fee in proportion to the eliminated inspection activities. All other requirements of the Commission permit for the facility shall be applicable. When a water supply or sewage collection and disposal system authorized under this section is completed, the person constructing the system shall file with the Commission as a permanent record a certified copy of the plans in full, showing the work as built. The record shall include the information and be in the form that the Commission requires. A person found to have violated this section is not relieved from the requirement to secure and pay for a permit and comply with all other applicable provisions of this section.