OWTS Licensed Professionals

The RIDEM OWTS (Onsite Wastewater Treatment Systems) Permitting program licenses five different categories of OWTS Professionals. There are four types of septic designers (Class-I, Class-II, Class-III, and Class-IV) and licensed Installers. An individual seeking to obtain one of these licenses must apply for and pass a written exam pending they meet the minimum qualifications to apply. Licenses expire every 3 years and must be renewed upon expiration. Each license type requires a different prerequisite and allows the individual to perform differing septic work. An outline of each category can be found below, but for more information, visit our Rules and Regulations.


An Installer’s License authorizes an individual to install, construct, alter or repair an OWTS. Applicants for an Installer’s License will be required to demonstrate possession of and ability to properly use a level or transit and to obtain a passing grade on a written examination.

Class-I Designers

A Class I License authorizes the design of a repair to an OWTS, or any component thereof. A valid Installers license is required to apply.

Class-II Designers

A Class II License authorizes the design of an OWTS repair or OWTS for an alteration to a structure with certain stipulations or a New Building Construction under 900 GPD not requiring certain variances. Registration as a Professional Land Surveyor with the RI State Board of Registration for Professional Land Surveyors is required to apply.

Class-III Designers

A Class III license authorizes the design of any OWTS. Class-III designers no longer need to pass an examination; however, the applicant must still apply for the license and must have be a current Professional Engineer in either Civil or Environmental.

Class IV Soil Evaluator's License

A Class IV license authorizes the performance of soil evaluations. An applicant must prove they meet the eligibility requirements outlined in the Regulations and must separately pass a written and field exam.