Thank you to everyone who reports issues
Every question in our bank has been written and reviewed carefully, but with thousands of problems spanning a dozen engineering disciplines, errors happen. When a user takes the time to work through a problem, verify the math, and send us a detailed report — that’s a genuine contribution to the quality of the question bank for every future test-taker. We read every report, verify every claim independently, and push fixes as quickly as possible. This page is our public record of confirmed corrections.
How to Report an Issue
If you believe a question has a wrong answer, a calculation error, or misleading wording, please contact us with:
- The Question ID (shown in the app when you review a question)
- A brief description of what you believe is wrong
- Your working, if you have it — even a rough sketch helps
We aim to respond and verify within 48 hours. If your report checks out, we will update the question bank and credit the correction here.
Confirmed Corrections
| Date | Exam | Topic | Description | Status |
|---|---|---|---|---|
| May 16, 2026 | PE Civil WRE | Open Channel Normal Depth (Q40310) | The trapezoidal-channel Manning calculation was understated. At 2.0 ft depth, the stated channel carries about 39.8 cfs, not 50 cfs; solving gives approximately 2.25 ft, so the closest listed answer was corrected to 2.2 ft. Found during a PE WRE content review. | Fixed |
| May 16, 2026 | PE Civil WRE | Geomembrane Leakage Comparison (Q40153) | The compacted clay liner unit conversion and geomembrane equivalent-depth conversion were corrected. The comparison is now approximately 20,000 times less leakage for the intact geomembrane under the stated assumptions. Found during a PE WRE content review. | Fixed |
| May 16, 2026 | PE Civil WRE | Advection-Dispersion Concentration (Q40146) | The explanation previously computed about 482 mg/L from the stated 1-D advection-dispersion model but then selected 310 mg/L using an unsupported attenuation adjustment. The option and solution were corrected to the nearest stated-model result, 480 mg/L. Found during a PE WRE content review. | Fixed |
| May 16, 2026 | PE Civil WRE | Secondary Clarifier Solids Loading (Q40099) | The SLR-controlled clarifier diameter should round up from about 64.5 ft to 65 ft per clarifier, not 64 ft. The answer option, explanation, and calculator steps were corrected. Found during a PE WRE content review. | Fixed |
| May 16, 2026 | PE Civil WRE | Ductile Iron Pressure Class (Q40062) | The stem asked for the minimum pressure class for a stated 200 psi total pressure. Pressure Class 200 is the minimum listed class that satisfies that requirement; the answer key was corrected from Pressure Class 250 to Pressure Class 200. Found during a PE WRE content review. | Fixed |
| May 16, 2026 | PE Civil WRE | Series Pipe Hazen-Williams Flow (Q40056) | The stated Hazen-Williams series-pipe equation and 50 ft available head solve to approximately 1,060 gpm. The prior listed answer of 290 gpm produced far less than the available head loss. The option set, explanation, and calculator steps were corrected. Found during a PE WRE content review. | Fixed |
| May 16, 2026 | PE Civil WRE | Darcy-Weisbach Friction Factor (Q40055) | Colebrook/Moody verification for Re = 186,000 and relative roughness 0.0017 gives f ≈ 0.0235, so the closest listed answer is 0.023. The answer key and explanation were corrected. Found during a PE WRE content review. | Fixed |
| May 15, 2026 | PE Civil WRE | Partially Full Pipe Depth Ratio (Q40103) | The full-flow Manning capacity for the stated 15-inch PVC sewer was understated. Using full-pipe area and hydraulic radius gives approximately 4.60 cfs, so the flow ratio is 2.40/4.60 = 0.52 and the closest supplied hydraulic-elements row is d/D = 0.50. The answer key, explanation, and calculator steps were corrected. Reported by Joshua P. | Fixed |
| May 15, 2026 | PE Civil WRE | Hazen-Williams Head Loss (Q40047) | The answer choices did not include the head loss produced by the stated Hazen-Williams formula and inputs. The corrected computation gives approximately 3.35 ft, so the closest answer was updated to 3.4 ft and the explanation/calculator steps were rebuilt. Reported by Joshua P. | Fixed |
| May 10, 2026 | PE Civil WRE | Compound Channel — Divided Flow (Q40081) | Answer key and explanation were inconsistent with the stated compound-channel geometry. The divided-flow calculation gives approximately 260 cfs, not 415 cfs, so the correct answer was changed from C to D and the solution/calculator steps were rebuilt. Reported by Joshua P. | Fixed |
| May 10, 2026 | PE Civil WRE | Modified Puls Routing (Q40033) | The stem referenced a storage-indication lookup but only supplied one storage-outflow point. A full lookup table and interpolation steps were added; the answer remains 48 cfs. Reported by Joshua P. | Fixed |
| May 3, 2026 | PE Civil WRE | Hydraulic Grade Line & EGL (Q40063) | The calculator steps field was incorrectly copied from a different question (pipe pressure class sizing) and bore no relation to the HGL/EGL problem. The EGL answer option was also corrected from 324.4 ft to 324.2 ft to reflect the exact computation (HGL = 323.846 ft; EGL = 323.846 + 0.388 = 324.234 ft). The explanation was updated to explicitly call out the psi → psf unit conversion (45 × 144 / 62.4). Reported by Joshua P. | Fixed |
| Apr 27, 2026 | PE Civil WRE | Open Channel Hydraulics | Answer key error in a channel-contraction specific-energy question. The explanation was also updated to correctly describe the direction of depth change in subcritical flow through a contraction. Reported by Joshua P. | Fixed |
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Last reviewed: June 13, 2026. Public correction notes were checked for clarity and internal-audit wording.