Primary-source standard
Federal certification and service-practice claims are checked against EPA and eCFR sources. When provider-specific details vary, the site tells users to confirm them with the chosen approved organization.
Original practice questions
Questions are written from public topic outlines and rules. They are not copied from the confidential EPA test bank. Explanations teach the controlling concept rather than claiming to reveal “real exam answers.”
Correction process
Material changes are recorded on the Updates page. Questions affected by a rule change are revised or removed before being reused.