Q: Can I be paid to fix a reverse osmosis filter without a plumbing license? Would fixing the filter be considered plumbing

A: Maryland Business Occupations and Professions Code, Section 12-101, defines the term plumbing, and the need for a license, as follows:

(n) Provide plumbing services

(1) “Provide plumbing services” means to install, maintain, extend, alter, or remove piping, a plumbing fixture, a plumbing appliance, a plumbing appurtenance, or other plumbing apparatus:

(i) within or adjacent to a building, structure, or property; and

(ii) in connection with:

1. a public or private disposal system, sanitary drainage facility, or storm drainage facility;

2. a venting system; or

3. a public or private water supply system.

(2) “Provide plumbing services” includes installing, repairing, servicing, and replacing gas piping, gas utilization equipment, and associated accessories.

(3) Except for the first connection to a potable water supply that is downstream of a backflow preventer and the final connection that discharges indirectly into a public or private disposal system, sanitary drainage facility, or storm drainage facility, “providing plumbing services” does not include using piping, equipment, or material only for:

(i) environmental control;

(ii) the incorporation of a liquid or gas into a product or into a process, including product development, in the manufacture or storage of a product;

(iii) the installation, alteration, repair, or removal of an automatic sprinkler system, related apparatus, or standpipe that is used only for fire protection; or

(iv) an overhead or underground fire line beginning from where water is used only for fire protection.

The Department of Labor, which is in charge of licensing and regulation of the plumbing trade, has further adopted the 2018 International Plumbing Code (International Code Council) as Maryland's plumbing code. A review of that code would be required to determine whether your proposed activity falls within the ambit of plumbing services that requires a license, unless it is specifically exempted by the above statutory language.

I would be concerned with the word, "maintain," in the above defintion of plumbing, in connection with your proposed work, as replacement of a filter sounds like a maintenance issue, but perhaps "maintain" is more strictly defined by the code as directed to the piping system or physical repairs to the parts of the system itself, and not a routine filter replacement. You may wish to consider applying for a license, of some sort, as there are a number of lesser licenses below master plumber license.