What is the FE Environmental exam pass rate?

In NCEES's most recent published data (fiscal year 2024-25), 67% of first-time takers passed FE Environmental, from a volume of 2,543 first-time examinees. Repeat takers passed at 37%. The 67% is the third-highest first-time rate of the seven FE disciplines, behind FE Mechanical at 69% and FE Chemical at 68%, and above FE Civil at 61%.

Is the FE Environmental exam easier than FE Civil?

By first-time pass rate, yes: 67% against 61%. But be careful what you conclude from that. The two exams draw different populations, and the gap says as much about who takes each exam as about the exams themselves. What is more useful: FE Environmental spreads 110 questions across 15 knowledge areas, so it rewards breadth over depth, and its two largest blocks are fluid mechanics and water/wastewater, which together can be nearly a third of the exam.

How long is the FE Environmental exam?

110 questions in 5 hours 20 minutes of actual testing time, inside a 6-hour appointment that also covers the nondisclosure agreement, an 8-minute tutorial and a 25-minute scheduled break. That works out to roughly 2.9 minutes per question, which has to cover reading the problem, finding the right relationship in the handbook, and computing.

What reference do you get in the FE Environmental exam?

The NCEES FE Reference Handbook, supplied onscreen. It is the only reference permitted: no printed copies, no design codes and no standards. (Among the PE exams, PE Civil: Water Resources and Environmental supplies design standards, including the Ten States Standards; PE Environmental supplies none.) Federal environmental statutes such as the Clean Water Act and RCRA appear in the ethics and professional practice topics, but at a knowledge level; the handbook does not reproduce them. Practicing with the handbook open from the start is the single highest-return habit, because finding a relationship quickly is a scoreable skill.

Why does the repeat pass rate drop to 37%?

It is the same pattern across every FE discipline, and it is the number worth taking seriously. A first attempt made without a real study plan is expensive: if it does not go well, you join a group that passes at close to half the first-time rate. Nothing in the data suggests a first attempt is a free diagnostic.

How hard is the FE Environmental exam?

Two thirds of first-time takers pass it (67% in NCEES Squared 2025, FY2024-25), which makes FE Environmental one of the friendlier FE disciplines on paper. That number is real, and it is also the least useful thing you can know about this exam. What matters is the shape of it: fifteen knowledge areas, under three minutes a question, and a repeat pass rate that falls to 37%.

Updated October 6, 2026 · by the FE → PE Prep team

67%

First-time pass

~2.9 min

Per question

Knowledge areas

FE Handbook

Only reference

Where it sits among the FE exams

NCEES publishes pass rates by discipline each year. These are first-time takers in fiscal year 2024-25, the most recent year NCEES has published, with repeat rates and first-time volumes alongside.

FE exam pass rates and first-time examinee volumes by discipline, NCEES fiscal year 2024-25
Discipline	First time	Repeat	Volume
FE Mechanical	69%	37%	11,552
FE Chemical	68%	35%	1,873
FE Environmental	67%	37%	2,543
FE Electrical and Computer	64%	31%	5,882
FE Industrial and Systems	62%	25%	547
FE Civil	61%	32%	16,639
FE Other Disciplines	61%	29%	2,386

Third of seven, and six points above FE Civil. Before you read too much into that, notice the volume column: 2,543 first-time environmental candidates against 16,639 civil ones. These are different populations taking different exams, so the gap describes who takes each exam at least as much as it describes the exams. The comparison is worth making, but it is not a difficulty ranking.

The number that deserves more attention is in the third column. Repeat takers pass at 37%, and the same drop shows up in every FE discipline. An unprepared first attempt is not a free diagnostic: fall short, and you join a group that passes at about half the first-time rate.

What the exam actually asks of you

110 questions in 5 hours 20 minutes of testing, inside a 6-hour appointment that also holds the nondisclosure agreement, an 8-minute tutorial and a 25-minute scheduled break. That is about 2.9 minutes per question: enough to read a problem, find a relationship in the handbook, and compute it, and not much more. Your only reference is the NCEES FE Reference Handbook, supplied onscreen. No codes, no standards, no printed copies.

The specification spreads those 110 questions across fifteen knowledge areas. Two of them carry up to eighteen questions each; the smallest carries three. Study time distributed evenly across the list is study time spent badly.

FE Environmental knowledge areas and question counts, per the NCEES specification effective July 2020
Knowledge area	Questions
Fluid Mechanics and HydraulicsTied for the largest block. Continuity, energy, pipe flow, pumps, open channels.	12–18
Water and WastewaterThe other largest block: treatment processes, loading rates, disinfection, sludge.	12–18
Surface Water Resources and HydrologyRainfall-runoff, the rational method, routing, water budgets.	9–14
Groundwater, Soils, and SedimentsDarcy, wells, contaminant transport, remediation.	8–12
Air Quality and ControlEmissions, dispersion, and control equipment.	8–12
Environmental ChemistryStoichiometry, equilibria, kinetics, partitioning.	7–11
Fundamental PrinciplesPopulation projections and demand, reactor models, materials science.	7–11
Solid and Hazardous WasteGeneration rates, landfills, hazardous-waste handling.	7–11
MathematicsAlgebra, trigonometry, calculus, numerical methods.	5–8
Ethics and Professional PracticeMostly qualitative. Includes compliance with federal statutes such as the CWA, CAA and RCRA.	5–8
Engineering EconomicsTime value of money, capital recovery, alternatives.	5–8
Probability and StatisticsDistributions, confidence intervals, regression, hypothesis testing.	4–6
Health Hazards and Risk AssessmentDose-response, exposure and intake, noise and occupational limits.	4–6
Energy and EnvironmentMostly qualitative: conventional and alternative sources, their environmental impacts.	4–6
ThermodynamicsThe smallest block on the exam.	3–5

Fluid mechanics and water/wastewater sit at the top, and between them they can account for nearly a third of the exam. Thermodynamics sits at the bottom with three to five questions. If you are deciding what to review in your last two weeks, the top four rows are worth more than the bottom six combined.

Two problems from our question bank

Difficulty is easier to judge from a question than from a percentage. These come from our free FE Environmental set, drawn from two of the three largest knowledge areas. Try each one before opening the solution, and read the note on the wrong answers afterward. That is where the exam actually lives.

The rational method, and why three options are the same physics

Surface water hydrology is up to 14 questions, and the rational method is the handbook's formula for peak discharge. It is worth looking hard at what the wrong answers are.

1
easy
A. Runoff & water budget
An urban catchment of 12 ha has a runoff coefficient of 0.70. The design rainfall intensity, for a storm lasting the catchment's time of concentration, is 90 mm/h. The peak runoff rate is most nearly:
Figure — drag or pinch to move around
1. 0.756 m³/s
2. 0.843 m³/s
3. 2.10 m³/s
4. 3.00 m³/s
Show the answer & worked solution
Answer: C.2.10 m³/s
The handbook's Rational Formula $Q = CIA$ works in any consistent units. With $i = 90\text{ mm/h} = \dfrac{90/1000\text{ m}}{3600\text{ s}} = 2.50\times10^{-5}$ m/s and $A = 12\text{ ha} = 120{,}000$ m², $Q = (0.70)(2.50\times10^{-5})(120{,}000) = 2.10$ m³/s. (The same thing in one step: $Q = CiA/360$ with $i$ in mm/h and $A$ in ha.) Distractors: the runoff coefficient $C$ left out (treated as 1); only the millimeters converted to meters ( $CiA/1000$ ), with the hectares and the hours left unconverted; and the handbook's U.S. form used with $i = 90/25.4 = 3.54$ in./hr but the 12 ha entered as if they were acres (1 ha = 2.47 acres), then the cfs converted to m³/s.

What the distractors teach

Only one distractor is a physics mistake: leaving out the runoff coefficient, as if every drop ran off, gives 3.00 m³/s. The other two are unit-conversion errors. Convert only millimeters to meters (CiA/1000) and you get 0.756. Switch to the handbook's U.S. form, convert 90 mm/h to 3.54 in./hr but enter the 12 ha as 12 acres, and you get 0.843. Same equation, same understanding, wrong units. On an exam that runs in both SI and US customary units, that is the failure mode to drill.

Continuity through a contraction

Fluid mechanics is one of the two twelve-to-eighteen-question blocks. This one is three lines of algebra, and it still catches people.

2
medium
A. Fluid statics & dynamics
Water flows steadily through a pipe that contracts from a diameter $D_1 = 200$ mm to $D_2 = 150$ mm. The upstream velocity is $V_1 = 1.5$ m/s. The velocity in the smaller section is most nearly:
Figure — drag or pinch to move around
1. 0.844 m/s
2. 2 m/s
3. 2.67 m/s
4. 4.74 m/s
Show the answer & worked solution
Answer: C.2.67 m/s
Continuity (FE Reference Handbook 10.6 p. 185): the same flow $Q=Av$ passes both sections, so $A_1V_1=A_2V_2$ . With $A=\pi D^2/4$ the $\pi/4$ cancels, leaving $V_2=V_1\left(\dfrac{D_1}{D_2}\right)^2=1.5\left(\dfrac{200}{150}\right)^2=2.67$ m/s, faster in the smaller section, as it must be. Distractors: the diameter ratio used un-squared, $V_1D_1/D_2$ (2 m/s), forgetting that area goes as $D^2$ ; the area ratio inverted, $V_1(D_2/D_1)^2$ (0.844 m/s), which would have the water slow down in the smaller section; and the ratio squared twice, $V_1(D_1/D_2)^4$ (4.74 m/s), the area-ratio squaring applied a second time.

What the distractors teach

Every wrong answer comes from mishandling the same square. Use the diameter ratio without squaring it and you get 2 m/s. Square it twice and you get 4.74. Invert the area ratio and you get 0.844, with the water slowing down as the pipe narrows. The relationship is not hard; keeping area proportional to diameter squared under time pressure is.

How to prepare for it

Weight your study time to the specification, not to your comfort. Fluid mechanics, water and wastewater, surface water and groundwater are roughly two-fifths of the exam between them. Thermodynamics is three to five questions.
Practice with the handbook open from day one. It is your only reference, and lookup speed is worth points. Knowing that a relationship exists is not the same as finding it inside three minutes.
Drill units, not just methods. The exam runs in both SI and US customary units, and as the rational-method problem above shows, a conversion done halfway produces an answer that is sitting right there in the option list looking reasonable.
Work problems under time. Breadth exams are lost on the clock, not on the concepts. 2.9 minutes is the whole budget, including reading.
Take the first attempt seriously. With repeat takers passing at 37%, the cheapest attempt is the one you prepared for.

For the cross-discipline picture, with every FE exam's rates side by side, see how hard is the FE exam?, and if you are weighing a first attempt against a retake, what actually works the second time.

Common questions

What is the FE Environmental exam pass rate?: In NCEES's most recent published data (fiscal year 2024-25), 67% of first-time takers passed FE Environmental, from a volume of 2,543 first-time examinees. Repeat takers passed at 37%. The 67% is the third-highest first-time rate of the seven FE disciplines, behind FE Mechanical at 69% and FE Chemical at 68%, and above FE Civil at 61%.
Is the FE Environmental exam easier than FE Civil?: By first-time pass rate, yes: 67% against 61%. But be careful what you conclude from that. The two exams draw different populations, and the gap says as much about who takes each exam as about the exams themselves. What is more useful: FE Environmental spreads 110 questions across 15 knowledge areas, so it rewards breadth over depth, and its two largest blocks are fluid mechanics and water/wastewater, which together can be nearly a third of the exam.
How long is the FE Environmental exam?: 110 questions in 5 hours 20 minutes of actual testing time, inside a 6-hour appointment that also covers the nondisclosure agreement, an 8-minute tutorial and a 25-minute scheduled break. That works out to roughly 2.9 minutes per question, which has to cover reading the problem, finding the right relationship in the handbook, and computing.
What reference do you get in the FE Environmental exam?: The NCEES FE Reference Handbook, supplied onscreen. It is the only reference permitted: no printed copies, no design codes and no standards. (Among the PE exams, PE Civil: Water Resources and Environmental supplies design standards, including the Ten States Standards; PE Environmental supplies none.) Federal environmental statutes such as the Clean Water Act and RCRA appear in the ethics and professional practice topics, but at a knowledge level; the handbook does not reproduce them. Practicing with the handbook open from the start is the single highest-return habit, because finding a relationship quickly is a scoreable skill.
Why does the repeat pass rate drop to 37%?: It is the same pattern across every FE discipline, and it is the number worth taking seriously. A first attempt made without a real study plan is expensive: if it does not go well, you join a group that passes at close to half the first-time rate. Nothing in the data suggests a first attempt is a free diagnostic.

Build your study plan

Tell us how long you have. We'll budget your hours across every knowledge area using the official NCEES question weights. The heaviest areas get the most time, which is the opposite of how most people study.

Work through eight more

Ten free FE Environmental problems in total (air quality, chemistry, risk, statistics, economics), each with the full worked solution and the reasoning behind every wrong answer. No signup.

Try the free FE Env set Explore FE Environmental

Pass rates are from the NCEES Squared 2025 annual report (fiscal year 2024-25); format and knowledge areas from the NCEES FE Environmental CBT specification effective July 2020. Specifications, fees and rates change over time; confirm current specifics at ncees.org. Independent study resource; not affiliated with, endorsed by, or sponsored by NCEES.