State Licensing Trends for Water Treatment Professionals

Aug. 26, 2022
State licensing requirements differ at the state level, including for Plumber and Specialty licenses


Occupational licensing has grown significantly over the last 60 years, comprising nearly 25% of the U.S. workforce, up from 5% nearly 60 years ago.1 Growth in this sector has incited states and local municipalities to rely on professional certification and educational programs to support the adoption and implementation of occupational licensing. Requirements at the state level for water treatment applications vary significantly between a Plumber License and Specialty License.  

State legislatures have their processes for adopting general licenses as well as Specialty Licenses for the water treatment industry. For purposes of this report, a Specialty License is defined as a license that is issued under the authority of a state occupational licensing board, department, and/or agency that allows the license to perform work within limits established by the relevant entity. Currently, 20 states require a Specialty License for water treatment and/or conditioning applications. Sixteen states require a Plumber License. Seven states have no state-wide license, and another seven states have no licensing requirements per state code. In this report, an analysis will be conducted into each state’s respective licensing requirements. Below is an overview of each state and the various licensures required.   

Comparative Analysis – State Licensing 

State licensing requirements vary significantly on a multitude of factors including educational and work-related experience as well as the scope of work permitted. Water treatment professions fall under two major licensing categories – Plumbing Licenses and Specialty Licenses. Some states have exemptions or do not explicitly mention actions outlined for water treatment and conditioning applications. To help understand the intricacies of each state, a comparative analysis of plumbing codes, licenses and implications from the water treatment industry at large may provide insight into the associated legislative and regulatory processes.  

Plumbing Codes

Water treatment and conditioning applications are inherently tied to plumbing systems, so it is helpful to understand the role of codes and regulations at the state or local level. Plumbing codes and licensure programs related to the water treatment industry are administered at the state level, and the work permitted falls in alignment with the state plumbing code. These codes can and do differ from state to state and are usually enforced through regulatory and legislative actions. Many states follow a version of the Uniform Plumbing Code (UPC) or the International Plumbing Code (IPC). Some often take provisions from these sources and develop a specialty code specific to the state’s desired intentions. Other states do not have a statewide plumbing code, allowing local municipalities to take charge of regulation and enforcement.  

Plumbing is usually defined within the administrative code in a “plumbing work” or “plumbing means” section. In some cases, water treatment and conditioning are explicitly called out as a part of “plumbing” (e.g. West Virginia). Majority of states that have a Plumber License define “plumbing work” to include fixtures, apparatuses or devices that are connected to plumbing or the distribution of potable water. This description encompasses water treatment devices or conditioning applications, as they are connected to the distribution of potable water supply. States with a Plumbing License have varying levels of expertise including an Apprentice, Journey Worker, and Master Plumbing license. The requirements for certification in these programs are usually dependent on the completion of a vocational or trade school curriculum, sponsorship by a licensed plumbing company, training in specific job-related functions, and familiarity with local/state and regulatory codes, before being followed by a written examination. The process for licensing and certification, like many things at the state level, varies.  


There are exemptions specified in many state programs. Louisiana is a prime example of a unique exemption. As a state that requires a Plumber License, Louisiana has a provision that allows an individual to conduct maintenance work on plumbing fixtures with no plumbing license. However, this is strictly for the maintenance of plumbing fixtures and not the initial installation of such devices. Continuing along the parallel of exemptions, states like Florida assert that the installation and maintenance of water conditioning units do not require individuals to be licensed to perform such activities. This sort of language specifically mentioning the exemption of conditioning or softening applications is prevalent in Illinois, Indiana and Montana. However, Idaho administrative code differs slightly and declares an exemption for conditioning applications, but specifically asserts that water-treating equipment falls under the scope of plumbing. Washington is somewhat on the opposite end of this spectrum, as the installation of water softening or treatment equipment into a water system is not considered in the scope of “plumbing” and does not call for a license. Michigan on the other hand, in the State Plumbing Act, designates an exemption for both water treatment and filtering equipment. This variation in definition and scope in exemption and Plumbing License states often presents difficulties for water treatment professionals to fully acknowledge the requirements. Thus, a large portion of states across the country have incorporated a sort of Specialty License to provide clarity. 

Specialty License

Specialty Licenses also vary to some extent at the state level. As examined in exemption states, there is a differentiation in the classification for the water treatment industry between conditioning and treatment applications. Conditioning is often related to water that has been treated by one or more processes (adsorption, deionization, filtration, softening, reverse osmosis, etc.) to improve the water's usefulness and/or aesthetic quality by reducing undesirable substances (iron, hardness, etc.) or undesirable conditions (color, taste, odor, etc.). States have an array of approaches for defining water conditioning or treatment. These varying definitions also influence the branding of each state’s licensure program in this sector, fluctuating from a restricted/limited plumbing license to a water conditioning contractor/installer or a water treatment technician licensure. States, where water conditioning or softening applications fall under the umbrella of a Specialty License include Alaska, Arizona, California, Connecticut, and Utah. Some are more specific to certain treatment methods (e.g. Softening, Filtering, etc.) and will explicitly call out water treatment devices and other filtration equipment. These include Arkansas, Colorado, Kansas, Minnesota, Nevada, New Hampshire, North Dakota, Oregon, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Vermont, and Wisconsin. Some states utilize a restricted-plumber classification that is separate from a Plumbing License. Oregon is a prime example, as the state’s administrative code outlines a Limited Specialty Plumber Classification required for the installation and servicing of water treatment equipment.  

Like some plumbing license programs, the work permitted under a Specialty License varies. As previously mentioned, some states will require a license or certification for condition/softening applications but will not mention treatment devices, subjecting the installation of treatment devices through another license. Arizona, for instance, has three separate classifications for water conditioning for residential, commercial and duality work. California is another interesting example, as the state allows for a valid Class C-55 water conditioning contractor’s license or Class C-36 plumbing contractor’s license to conduct work in this sector. On the other hand, Minnesota and Colorado have robust programs for water treatment and condition applications. The Minnesota code outlines three levels for water conditioning: Water Conditioning Contractor, Water Conditioning Journey Worker, and Water Conditioning Master. Colorado has three Specialty Licenses for water treatment professionals: Water Conditioning Contractor, Water Conditioning Installer, and Water Conditioning Principal.  

Each of these licenses, certifications, and classifications has different educational and work experience-related requirements. Oregon has a robust program that requires knowledge of codes, regulations and training in specific water treatment and plumbing work. Colorado has taken an innovative approach to this aspect of licensing and certification by allowing a nationally recognized program to certify an individual for compliance with the licensure program. However, Colorado still requires registration with the governing entity in the state.  

Overall, a Specialty License for water treatment and conditioning applications and the requirements for such licensing vary from state to state and verify the current regulatory requirements as these are subject to change.  

About the Author

Jordan Kari

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