# Water Treatment Operator Grades in California > California water treatment (T1 to T5) and distribution (D1 to D5) operator grades: how systems are classified, how to qualify, and how to renew. Source: https://www.exoduswater.com/post/california-water-operator-certification-grades Operations October 30, 2026Exodus Water Services # California Water Operator Certification Grades: T1 to T5 and D1 to D5 Explained California water treatment (T1 to T5) and distribution (D1 to D5) operator grades: how systems are classified, how to qualify, and how to renew. **Short answer:** California certifies drinking water operators in two tracks with five grades each: **water treatment operators, T1 through T5** , and **water distribution operators, D1 through D5** . Every treatment plant and distribution system is also classified T1 to T5 or D1 to D5, and the **chief operator must hold a certificate at least equal to that classification** (Title 22, California Code of Regulations, sections 63765 and 63770). The program is run by the State Water Board’s Drinking Water Operator Certification Program, which certifies about 35,000 treatment and distribution operators. Certificates are valid for three years and are renewed with continuing education. This guide explains how the grades work for both operators and the water systems that employ them. ## Who needs a water operator certificate? The State Water Board’s renewal guidance is direct: to operate a water distribution system you must hold a current, valid distribution operator certificate, and to operate a water treatment plant you must hold a current, valid water treatment operator certificate. To operate a water recycling treatment plant you need either a valid wastewater operator certificate or a valid water treatment operator certificate. There are no exceptions, and operating without the right certificate can bring criminal and civil liability. Treatment operators who are not designated as chief or shift operators must still be certified, but may hold a certificate of any grade (22 CCR 63765(b)). Wastewater treatment plant operators are certified under a separate program and separate regulations in Title 23\. This article covers drinking water operators only. ## Chief operator vs shift operator Title 22 defines two roles that drive the grade requirements: - **Chief operator:** the person with overall responsibility for the day-to-day, hands-on operation of a water treatment facility or distribution system (22 CCR 63750.25). - **Shift operator:** the person in direct charge of operating a treatment facility or distribution system for a specified period of the day (22 CCR 63750.70). Each water supplier must designate at least one chief operator for each treatment facility and each distribution system, and at least one shift operator for each operating shift (22 CCR 64413.5 and 64413.7). ## Treatment grades T1 to T5 ### How a treatment plant is classified Each water treatment facility is classified by a point total under 22 CCR 64413.1: | Total points | Facility class | | ------------- | -------------- | | Less than 20 | T1 | | 20 through 39 | T2 | | 40 through 59 | T3 | | 60 through 79 | T4 | | 80 or more | T5 | Points come from thirteen factors, including the type of source water, the influent water’s microbiological quality, turbidity, nitrate, nitrite, and perchlorate, other chemical and radiological contaminants, the filtration and disinfection processes used, and plant flow. Two examples from the regulation: - **Source water:** 2 points for groundwater or purchased treated water that meets drinking water standards; 5 points for water that includes surface water or groundwater under the direct influence of surface water. - **Flow:** 2 points per million gallons per day of maximum permitted capacity, up to 50 points. ### Staffing requirements for treatment plants | Facility class | Minimum chief operator grade | Minimum shift operator grade | | -------------- | ---------------------------- | ---------------------------- | | T1 | T1 | T1 | | T2 | T2 | T1 | | T3 | T3 | T2 | | T4 | T4 | T3 | | T5 | T5 | T3 | Source: Table 63765-A, 22 CCR 63765. A chief or shift operator must be **on site at all times the facility is operating** , unless the system’s approved operations plan shows equal oversight and reliability with unmanned operation or reduced certification. In that case the operator must be reachable within one hour (22 CCR 64413.5). ## Distribution grades D1 to D5 ### How a distribution system is classified The distribution system of each community and nontransient-noncommunity water system is classified by population served (22 CCR 64413.3): | Population served | System class | | ------------------------ | ------------ | | 1,000 or less | D1 | | 1,001 through 10,000 | D2 | | 10,001 through 50,000 | D3 | | 50,001 through 5 million | D4 | | Greater than 5 million | D5 | For a wholesaler, the population includes customers served by its retailers. A system serving 5 million people or fewer moves **up one class** if its points exceed 20\. Points are assigned for: - pressure zones: 0 for up to three, 4 for four to ten, 6 for more than ten; - disinfectants: 5 if a single disinfectant or ammonia is applied in the distribution system, 8 if multiple disinfectants are used; - largest pump: 4 for up to 50 horsepower, 6 for 50 or more; - storage reservoirs: 4 for one to five, 6 for more than five; - uncovered distribution reservoirs: 10; and - customers also served by a non-potable distribution system: 6. ### Staffing requirements for distribution systems | System class | Minimum chief operator grade | Minimum shift operator grade | | ------------ | ---------------------------- | ---------------------------- | | D1 | D1 | D1 | | D2 | D2 | D1 | | D3 | D3 | D2 | | D4 | D4 | D3 | | D5 | D5 | D3 | Source: Table 63770-A, 22 CCR 63770. The chief or shift operator must be on site or reachable within one hour (22 CCR 64413.7). Section 63770 also lists decisions that only certified distribution operators may make, such as installing, repairing, and disinfecting water mains, rehabilitating wells, draining and cleaning reservoirs, and after-hours emergency response. ## How to qualify for each grade Each grade has two steps: meet the minimum qualifications to sit for the exam, then meet the eligibility criteria for the certificate. You must pass the exam **within the three years before** you apply for certification. The table below summarizes the State Water Board’s minimum requirements sheets (revised November 2024). | Grade | To take the exam | Experience needed for the certificate | | ------- | ---------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------- | | T1 / D1 | High school diploma or GED | None | | T2 / D2 | Diploma or GED, plus one specialized training course | None | | T3 | Diploma or GED, plus two courses, including one on drinking water treatment fundamentals | 1 year as a certified T2 operator at a T2 facility or higher, plus 1 more year as a certified treatment operator | | D3 | Valid D2 certificate, plus two courses, including one in water supply principles | 1 year as a certified D2 operator at a D2 system or higher, plus 1 more year as a certified distribution operator | | T4 / D4 | Valid T3 or D3 certificate, plus three courses | 1 year at the grade below (for T4, with shift or chief designation), plus 3 more years as a certified operator | | T5 / D5 | Valid T4 or D4 certificate, plus four courses | 2 years at the grade below (for T5, with shift or chief designation), plus 3 more years as a certified operator | A “course” here means a 36-hour, 3.6 CEU, or 3-semester-unit course of specialized training in drinking water or wastewater subjects from an accredited institution or an IACET-accredited provider. **Substitutions.** The diploma requirement for the first grades can also be met by completing the State Water Board’s Basic Small Water Systems Operations course, or one year operating a facility that required an understanding of the relevant equipment. Some of the additional experience can be replaced by education: an associate degree or certificate in water or wastewater technology with at least 15 units of science counts as 1 year, a bachelor’s degree in engineering or science as 1.5 years, and a master’s degree as 2 years. For treatment grades, experience as a certified wastewater operator can count for up to 2 years, at two months of wastewater experience per one month of credit. **Applying.** Exam and certification applications are filed through the State Water Board’s online portal (OCIS) or with the forms on its operator certification page. The T5 exam is offered on a set schedule: for the winter 2027 exam, applications must be postmarked by December 11, 2026. ## How to renew a California operator certificate | Requirement | Rule | | ----------------------------- | -------------------------------------------------------------------------- | | Certificate term | Three years (22 CCR 63840(d)) | | When to apply | At least 120 days, but no more than 180 days, before expiration (63840(b)) | | Contact hours, Grade 1 | 12 | | Contact hours, Grade 2 | 16 | | Contact hours, Grade 3 | 24 | | Contact hours, Grades 4 and 5 | 36 | | Safety courses | No more than 25 percent of the hours | Source: Table 63840-A, 22 CCR 63840. A few rules that catch operators off guard: - **Contact hours count only if earned during the renewal period** , which runs from issue or renewal until six months past expiration. Hours used late on one renewal cannot be reused on the next. - **Send hours with the renewal.** If contact hours reach the Office of Operator Certification less than 45 days before expiration, the office may not have time to process the renewal before the certificate expires. - **Operators holding both certificates** may apply the same hours to both, if earned within each renewal period. - **A course must be at least 50 minutes** to count as one contact hour. - **Reinstatement windows are short.** A certificate revoked for missing contact hours may be reinstated within six months; one revoked only for nonpayment, within one year. A certificate revoked for more than one year cannot be renewed, and the operator must pass an exam again (22 CCR 63845). Fees for exams, certificates, and renewals are set in 22 CCR 63850 and the State Water Board’s current fee schedule. ## What this means for water systems For a water system, the classification of each treatment facility and distribution system is the starting point. It sets the minimum grade for your chief and shift operators. If your designated chief operator leaves, retires, or lets a certificate lapse, the system no longer meets its staffing requirement. Keep a list of every certified operator, their grade, and their expiration date, and check it well ahead of each 120-day renewal deadline. Our guide to [operator of record requirements for small California water systems](https://www.exoduswater.com/post/operator-of-record-requirements-small-california-water-systems) covers what to do when that happens. ## How Exodus helps Exodus Water Services operators hold State Water Resources Control Board water treatment and distribution operator certifications. We provide qualified, appropriately graded California-certified operators to meet DDW staffing requirements, for a whole system or a single chief or shift operator seat. See our [Operator of Record services](https://www.exoduswater.com/operator-of-record) , read about [the advantages of remote water operators](https://www.exoduswater.com/post/advantages-of-remote-water-operators-in-utilities-why-a-remote-operator-for-water-systems-is-essent) , or [contact us](https://www.exoduswater.com/contact-us) . Call (805) 991-7333 to discuss coverage. ## Frequently asked questions **What are the California water operator certification grades?**Water treatment operators are certified T1 through T5, and water distribution operators D1 through D5\. Grade 1 is the entry level and Grade 5 is the highest. **How is the required chief operator grade determined?**By the classification of the treatment facility or distribution system. The chief operator’s certificate must be at least equal to the classification, under 22 CCR 63765 for treatment and 63770 for distribution. **How is a distribution system classified?**By population served, from D1 for 1,000 people or fewer to D5 for more than 5 million. Systems serving 5 million or fewer move up one class if points for pressure zones, disinfectants, pumps, reservoirs, and non-potable service exceed 20. **Do I need experience to get a T1 or D1 certificate?**No. You need a high school diploma or GED, or an approved substitute, and a passing exam score within the three years before you apply. **How often do California water operator certificates renew?**Every three years. The renewal application, fee, and continuing education hours are due at least 120 days before the certificate expires. **How many contact hours do I need to renew?**12 hours for Grade 1, 16 for Grade 2, 24 for Grade 3, and 36 for Grades 4 and 5, with no more than 25 percent in safety topics. **Can a shift operator hold a lower grade than the chief operator?**Yes. At T2, T3, and T4 facilities and D2, D3, and D4 systems, the shift operator may hold one grade below the classification. At T5 and D5, the minimum shift operator grade is T3 or D3. **Can I look up whether an operator is certified?**Yes. The State Water Board publishes a searchable list of certified drinking water operators on its operator certification site. Last reviewed: October 30, 2026. ## Sources - State Water Board, [Drinking Water Operator Certification Program](https://www.waterboards.ca.gov/drinking%5Fwater/certlic/occupations/DWopcert.html) - State Water Board, [Operator Certification Statutes, Regulations, and Other Laws, September 2026 (PDF)](https://www.waterboards.ca.gov/drinking%5Fwater/certlic/occupations/documents/current-regulations.pdf) : 22 CCR 63750.25, 63750.70, 63765, 63770, 63840, 63845, 63850, 64413.1, 64413.3, 64413.5, and 64413.7 - State Water Board, [Drinking Water Treatment Minimum Requirements (PDF)](https://www.waterboards.ca.gov/drinking%5Fwater/certlic/occupations/documents/opcert/mqsforexamcert.pdf) , revised November 2024 - State Water Board, [Drinking Water Distribution Minimum Requirements (PDF)](https://www.waterboards.ca.gov/drinking%5Fwater/certlic/occupations/documents/opcert/distribution%5Fqualifications.pdf) , revised November 2024 - State Water Board, [Renewal and Continuing Education FAQs (PDF)](https://www.waterboards.ca.gov/drinking%5Fwater/certlic/occupations/documents/opcert/renewalfaqs.pdf) , updated February 2026 - State Water Board, [Searchable list of certified drinking water operators](https://wbapps.waterboards.ca.gov/opcert/PublicSearchDw.xhtml) ## How Exodus can help - Related service [Operator of Record services ](https://www.exoduswater.com/operator-of-record) - Free tool [Compliance Deadline Checker ](https://www.exoduswater.com/tools#deadline-checker) [Request a Compliance Review](https://www.exoduswater.com/contact-us?service=oor) [(805) 991-7333](tel:+18059917333) [Browse all articles](https://www.exoduswater.com/blog) Related service [Operator of Record services](https://www.exoduswater.com/operator-of-record)