(1) Any person selling or dealing in plumbing materials or supplies, but not engaged in the installation, alteration, repairing, or removal of plumbing, shall not be required to employ or have a licensed plumber in charge.

(2) Nothing in this article shall be construed to require any individual to hold a license to perform plumbing work on his own property or residence, nor shall it prevent a person from employing an individual on either a full- or a part-time basis to do routine repair, maintenance, and replacement of sinks, faucets, drains, showers, tubs, toilets, and domestic appliances and equipment equipped with backflow preventers; except that, if such property or residence is intended for sale or resale by a person engaged in the business of constructing or remodeling such facilities or structures or is rental property which is occupied or is to be occupied by tenants for lodging, either transient or permanent, or is a commercial or industrial building, the owner shall be responsible for and the property shall be subject to all of the provisions of this article pertaining to licensing, unless specifically exempted therein.

(3) Nothing in this article shall be construed to apply to the manufacture of housing which is subject to the provisions of part 7 of article 32 of title 24, C.R.S., or the installation of individual residential or temporary construction units of manufactured housing water and sewer hookups inspected pursuant to section 12-58-104.

(4) Persons who are engaged in the business of inspecting, testing, and repairing backflow prevention devices shall be exempt from licensure under this article, except when such persons engage in the installation and removal of such devices.

(5) Nothing in this article shall be construed to require either that employees of the federal government who perform plumbing work on federal property shall be required to be licensed before doing plumbing work on such property or that the plumbing work performed on such property shall be regulated pursuant to this article.

(6) (a) Nothing in this article requires a plumbing license, registration, or permit to perform:

(I) The installation, extension, alteration, or maintenance, including the related water piping and the indirect waste piping, of domestic appliances equipped with backflow preventers, including lawn sprinkling systems; residential ice makers, humidifiers, electrostatic filter washers, or water heating appliances; building heating appliances and systems; fire protection systems except for multipurpose residential fire sprinkler systems in one- and two-family dwellings and townhouses that are part of the potable water supply; air conditioning installations; process and industrial equipment and piping systems; or indirect drainage systems not a part of a sanitary sewer system; or

(II) The repair and replacement of garbage disposal units and dishwashers directly connected to the sanitary sewer system, including the necessary replacement of all tail pipes and traps, or the repair, maintenance, and replacement of sinks, faucets, drains, showers, tubs, and toilets.

(b) Notwithstanding paragraph (a) of this subsection (6), "plumbing" does not include:

(I) Installations, extensions, improvements, remodeling, additions, and alterations in water and sewer systems owned or acquired by counties pursuant to article 20 of title 30, C.R.S., cities and towns pursuant to article 35 of title 31, C.R.S., or water and sanitation districts pursuant to article 1 or article 4 of title 32, C.R.S.;

(II) Installations, extensions, improvements, remodeling, additions, and alterations performed by contractors employed by counties, cities, towns, or water and sewer districts that connect to the plumbing system within a property line; or

(III) Performance, location, construction, alteration, installation, and use of on-site wastewater treatment systems pursuant to article 10 of title 25, C.R.S., which are located within a property line.