The ability to self-assess is a key component of learning and particularly of life-long learning. Knowledge surveys (KS) are a self-assessment tool where respondents rate their ability to answer a question or perform a skill rather than answer directly with knowledge content or by solving a problem as they would on an exam. KS were implemented in a junior level hydraulics class in three successive semesters, with a total of 64 students, to evaluate the accuracy of student self-assessments compared with instructor assessments (exams). Students' self-reported behaviors and attitudes towards KS were assessed through qualitative feedback surveys. Results of this study show that: (1) students are reasonably accurate self-assessors, (2) accuracy improves with feedback and practice during the semester, and (3) higher exam scores are correlated with both earlier and more engaged use of KS, and with more positive self-reported attitudes. Given the successful use of KS in this study, civil engineering faculty should be encouraged to use KS in their courses to stimulate metacognitive reflection and learning. Further, KS and self-assessment have the potential to be a significant tool for achieving the Accreditation Board for Engineering and Technology (ABET) student outcome for acquiring and applying new knowledge, both in academic and professional settings as civil engineers adapt to an ever-changing world.