Median Pay by Area
- Portland-South Portland
- $63,810 a year
- Northeast Maine (non-metro)
- $60,560 a year
- Southwest Maine (non-metro)
- $60,560 a year
- Bangor
- $58,980 a year
Maine wastewater operators
The steps from no certificate to a Maine Biological Grade 1 wastewater operator certificate, how to apply and take the exam, how to keep your certificate active and what operators earn. Every requirement links to the Maine Department of Environmental Protection (DEP) Wastewater Operator Certification Program, the NEIWPCC South Portland office that runs it day to day, or Maine's rule, Chapter 531.
DEP makes the final eligibility determination. Check with DEP before you apply.
Why it matters
Maine law makes it unlawful to operate a wastewater treatment plant unless its operator or operator in responsible charge is certified by DEP, and unlawful to do an operator's duties without being certified.
The owner of each licensed wastewater treatment plant must name at least one Operator in Responsible Charge (ORC) with a certificate at or above the plant's classification. Other employees supervised by the ORC may be certified but do not have to be.
A licensed professional engineer in good standing may be named the ORC without an operator certificate.
DEP oversees the program. The New England Interstate Water Pollution Control Commission (NEIWPCC) handles day-to-day administration from its South Portland office, which also houses the Joint Environmental Training Coordinating Committee (JETCC).
DEP classifies each plant as Biological Grades 1 to 5, Physical/Chemical (P/C) Grades 1 and 2, or Spray Irrigation Treatment System (SITS) Grades 1 and 2. Operator certificates use the same types and grades.
A certificate covers plants of the same classification or lower. A Biological certificate also covers a P/C or SITS plant of the same grade or lower.
Physical/Chemical certificates are used mostly at industrial treatment plants. Drinking water operator licenses are handled separately by the Maine Division of Environmental and Community Health.
Step 1
Every grade needs a high school diploma or GED. Biological Grade 1 needs no work experience.
Wastewater work experience means doing or supervising operational duties directly related to wastewater treatment, such as running and maintaining process equipment, lab work, sludge handling, process control and compliance.
Related work experience includes drinking water, industrial wastewater, wastewater collection and wastewater design. More than one year of military service counts as one year of related work experience.
Related education is coursework after high school in fields such as biology, chemistry, environmental science, engineering and water and wastewater treatment technology. Thirty semester credits count as one year of education, and a certificate from a DEP-accepted wastewater technology program counts as one year of wastewater work experience.
Step 2
Fill out the Wastewater Treatment Plant Certification Application, listing your education and every wastewater or related job with your duties, and sign it. Incomplete forms are returned.
Mail or email it to NEIWPCC-JETCC in South Portland with the nonrefundable $125 application fee, by check or credit card.
DEP reviews every application to decide which grade exam you may take. There are no application deadlines, and an approval is valid for two years.
Step 3
You may take a Biological Grade 2 to 5 exam before you have the experience for it. If you pass, DEP gives you an active certificate at the grade your experience supports and a provisional certificate at the grade you passed.
A provisional certificate cannot make you the ORC at that grade. Once you have the experience, your supervisor sends an Upgrade Request Form with a $125 fee. You must upgrade within 6 years of passing, or the provisional certificate expires.
After passing Biological Grade 1, you can upgrade to Grade 2 the same way once you have one year of wastewater experience, or four years of related work and education combined.
Step 4
NEIWPCC's Maine pages link WPI's exam resources: Need-to-Know Criteria, study guides, sample questions and the Wastewater Formula/Conversion Table, which is provided during the exam.
For the Spray Irrigation Treatment System exam, NEIWPCC publishes a SITS study guide.
Step 5
Once DEP approves you, PSI emails you a unique ID and scheduling instructions. You then schedule on PSI's website and pay PSI's exam fee online by credit card.
Biological and Physical/Chemical exams are on computer at PSI test centers anywhere in the United States. NEIWPCC lists Maine centers in Portland, Farmington and Presque Isle.
You can reschedule once without penalty if you contact PSI at least two business days ahead. Arriving more than 15 minutes late means you cannot test.
The SITS exam is on paper, offered as needed in Portland, Augusta, Bangor or Presque Isle. NEIWPCC schedules it with DEP after you apply, and the $125 is paid to NEIWPCC.
Step 6
Your result is given to you as soon as you finish. If you pass, PSI tells NEIWPCC, and your certificate and wallet card are mailed within four weeks. You do not need to do anything else.
Your first certificate period is no longer than two years and follows Maine's two-year renewal cycle.
Step 7
Certificates are renewed every two years by March 1. Odd-numbered certificates renew in odd-numbered years and even-numbered certificates in even-numbered years. NEIWPCC mails renewal notices by October 1.
To renew, show at least 18 Training Contact Hours (TCHs) of DEP-approved training and pay the renewal fee, currently $125. SITS Grade 1 operators need 6 TCHs.
No more than 6 of the 18 TCHs may be safety or management training. Extra hours do not carry over, and a course (other than safety) cannot be used in two renewal cycles in a row.
DEP approves all training. Many Maine providers get courses pre-approved; for other courses, send a TCH Request Form to NEIWPCC. One college credit in chemistry, math, biology, engineering or environmental science equals 10 TCHs.
If you miss March 1, your certificate becomes inactive and you cannot be an ORC. You have a six-month grace period to finish renewing with a $100 late fee. After that you must retake the exam, and after two years your certification is removed.
Exam day
Maine uses a customized exam built by DEP with Water Professionals International (WPI, formerly the Association of Boards of Certification). PSI gives it on computer.
Each exam has 100 multiple-choice questions and up to 3 hours. You need at least 70% to pass.
Pencils, scratch paper and the ABC/WPI math formula sheet are provided. Bring two forms of ID (one a current government-issued photo ID with your signature) and a silent, non-programmable calculator without an alphabetic keypad or printing.
If you do not pass, you can retake the same grade as often as needed during your two-year approval, paying only PSI's fee each time. After two years, you apply again.
Operator Master has free practice questions with an explanation after every answer, a timed full-length practice exam and step-by-step math help built on the WPI formula table. It is an independent study tool, not the official exam.
Pay
The median pay for water and wastewater treatment plant and system operators in Maine was $61,870 a year ($29.74 an hour) in 2025, compared with $60,020 nationally. One in ten earned $49,220 or less, and one in ten earned $84,730 or more.
These federal figures cover drinking water and wastewater operators together, at every grade. Pay for a new operator is usually nearer the low end.
Moving up
Every grade also needs a high school diploma or GED and a passing exam. Related work experience and related education can replace part of the wastewater experience as shown; see the definitions in the first step. Chapter 531 has the exact wording.
From another state
If you hold a valid certificate from another state or country, DEP may certify you at a comparable grade without an exam. Your certificate must be in good standing and must have been earned by written exam.
You must still meet Maine's education and experience requirements. Use the same application, attach a copy of your current certificate and pay the $250 reciprocity fee to NEIWPCC.
Once certified, you follow Maine's two-year renewal requirements like every other operator.