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What is the difference between a Class D and Class C wastewater license?
Class D is the entry-level Texas wastewater license and needs no experience. Class C is the next grade: it builds on Class D and adds documented operating experience and a harder exam. Most small wastewater systems can be run by a Class D or C operator, depending on the system.
Last reviewed 2026-08-03
Class D
The entry license. No prior experience, an approved training course, and a closed-book exam. It qualifies you for entry-level operator work and is where nearly everyone starts.
Class C
The next grade up. It requires documented hands-on operating experience plus a more demanding exam, and it opens up more systems and higher-responsibility roles.
Common questions
- Which comes first?
- Class D, the entry grade, before Class C.
- Does Class C need experience?
- Yes, documented operating experience, unlike Class D.
- Should I start with D?
- Almost everyone starts at Class D, then moves up.