Groundwater Discharge Licenses

The DNREC Division of Water issues licenses for the various professions involved in designing, installing and maintaining on-site wastewater treatment and disposal systems. Licenses are granted under the state’s on-site systems regulations and with input from the On-Site Systems Advisory Board.

Contact Us

Div. of Water Licensing
302-739-9116

Digital DNREC Div. of Water License Fees

Any work performed on an on-site system treatment system in Delaware should be performed by a licensed contractor approved by the Board.

Groundwater discharge licenses are issued under the state’s Regulations Governing the Design, Installation and Operation of On-Site Wastewater Treatment and Disposal Systems (7 DE Admin. Code 7101) available as a PDF version with exhibits and attachments.

Licenses are applied for online, using the Digital DNREC ePermitting system.

Instructions: How to apply for a new Groundwater Discharge License

Instructions: How to renew a license

The ePermitting system offers online applications for licenses and permits throughout the department. It allows users to manage their own portfolio of licenses and permits.

Those unable to take advantage of the Digital DNREC ePermitting system can contact the Division of Water at 302-739-9116.

License Types and Licensee Lists

Groundwater discharge licenses are issued in eight different classes, focused on different aspects of systems design, installation and maintenance.

All on-site wastewater treatment and disposal system licensees are listed on the Delaware Open Data Portal in a data-set that is updated weekly.

Class A – Percolation Tester

Class A Licenses authorize the performance of percolation tests. (Class A Licensee List)

Class B – Designer

Class B licenses authorize the design of conventional on-site wastewater treatment and disposal systems which utilize gravity distribution systems for seepage beds and seepage trenches and certain standardized pressure distribution and disposal systems. (Class B Licensee List)

Class C – Designer

Class C licenses authorize the design of conventional, alternative and experimental on-site wastewater treatment and disposal systems and all pressure distribution systems. (Class C Licensee List)

Class D – Site Evaluator

Class D licenses authorize the performance of site evaluations. (Class D Licensee List)

Class E – System Contractor/Installer

Class E licenses authorize the construction and installation of wastewater treatment and disposal systems. (Class E Licensee List)

Class F – Liquid Waste Hauler

Class F licenses authorize the removal, transportation or disposal of the solid and liquid contents of septic tanks, cesspools, grease traps, seepage pits, holding tanks, portable toilets or other wastewater treatment or disposal facilities as specified and required under the Regulations. (Class F Licensee List)

Class H – System Inspector

Class H licenses authorize the inspection, investigation and data collection to make determinations regarding the operational condition of on-site wastewater treatment and disposal systems. (Class H Licensee List)

Class I – Construction Inspector

Class I licenses authorize the inspection of all new, replacement and repairs of small gravity on-site wastewater treatment and disposal systems, gravity on-site system component replacements and cover inspections for above grade gravity on-site wastewater treatment and disposal system. (Class I Licensee List)

License Applications

All new license applications must be submitted through Digital DNREC personal accounts and require submission of completed application forms (including two professional references signed and dated within the current calendar year).

The application must be reviewed and approved by the On-Site Systems Advisory Board. The board generally meets monthly. Applications must be received a minimum of 10 business days prior to the meeting date to be included in the monthly board meeting agenda.

Groundwater discharge licenses, once issued, must be renewed annually, prior to December 31 of each year.

Property owners who wish to conduct their own percolation testing, system design or system installation, on their own property and for their own use, may apply for a temporary Class A, B, or E license.

Please note that all fees are non-refundable.

Examinations

2026 Exam Dates

Feb. 12, 2026
May 14, 2026
Aug. 13, 2026
Nov. 12, 2026

Once the Delaware Onsite Systems Advisory Board approves an individual’s application, that individual is notified via email and is eligible to take the examination for that license type.

Examinations are scheduled quarterly — in February, May, August and November. Individuals are notified via email of examination details and examination grades. Exams will not be rescheduled once they have been assigned.

There are separate examinations for each license type. The examinations are comprised of multiple-choice and true/false questions relating to general knowledge of the scope of work for each license type and the Regulations Governing the Design, Installation and Operation of On-Site Wastewater Treatment and Disposal Systems (7 DE Admin. Code 7101).

Applicants must earn a score of 70% or higher to pass.

If the individual fails an examination, they must complete an approved prep course for that license type and reapply if they wish to sit for the exam again. If an individual does not attend a scheduled examination, the examination will not be rescheduled, and they will receive a zero.

Once the individual passes the examination, the license will be issued upon completion of the application by Department staff, and the individual will receive email notification with copies of the license card/certificate.

Continuing Education Training

Groundwater discharge licenses are issued for a one-year period. To renew, applicants must provide proof of at least 10 hours of approved training during that year.

Continuing education must be submitted through the individual’s Digital DNREC personal account, under the “Water Continuing Education” tab. Licensees are encouraged to submit their completed continuing education hours a minimum of 60 days prior to the license expiration date, to streamline the renew process and prevent potential delays or a lapse in license.

Submitted proof of continuing education must be approved by DNREC staff prior to the individual renewing the license(s).

The Board accepts requests for approval of continuing education training and courses. Instructions for submittal are at the top of the request form. Requests are reviewed monthly.

Submit request forms (with all required back up documentation) to DOWLicensing@delaware.gov.

License Renewals

Groundwater Discharge licenses can be renewed up to one year from expiration.

Once the renewal period has expired, individuals must reapply for license, including applicable fees and successfully completing the exam. Individuals who apply and pass the exam after the renewal period has expired will receive a new license number different from the license number previously issued.