100+ Free FE Environmental Practice Questions

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Question 1

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A linear regression of nitrate concentration (mg/L) versus time (years) gives slope b = 0.42 with standard error s_b = 0.10 and n = 22 data points. What is the t-statistic used to test whether the slope is significantly different from zero?

1.4

2.1

4.2

10.0

to track

2026 Statistics

Key Facts: FE Environmental Exam

110

Exam Questions

NCEES

5h 20m

Exam Duration

NCEES

$175

Exam Fee

NCEES 2026

~70%

First-Time Pass Rate

NCEES tables

Knowledge Areas

NCEES outline

200-300 hrs

Study Time

Recommended

FE Environmental has 110 questions in 5 hours 20 minutes (including the 25-minute scheduled break and tutorial). The $175 NCEES exam is computer-based at Pearson VUE and uses the on-screen NCEES FE Reference Handbook. First-time pass rates run roughly 67-74%. Plan 200-300 hours of study, with the heaviest weighting on water/wastewater (12-18 questions), environmental science and chemistry (11-17), and air quality (10-15).

Sample FE Environmental Practice Questions

Try these sample questions to test your FE Environmental exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1A linear regression of nitrate concentration (mg/L) versus time (years) gives slope b = 0.42 with standard error s_b = 0.10 and n = 22 data points. What is the t-statistic used to test whether the slope is significantly different from zero?

A.1.4

B.2.1

C.4.2

D.10.0

Explanation: The t-statistic is t = b / s_b = 0.42 / 0.10 = 4.2. With n - 2 = 20 degrees of freedom, |t| > 2.086 (two-tail, alpha = 0.05) so the slope is statistically significant. The t-test for a regression slope is in the FE Reference Handbook, Probability and Statistics section.

2The first-order decay rate constant for a contaminant is k = 0.23 day^-1. What is its half-life?

A.1.5 days

B.3.0 days

C.4.3 days

D.6.9 days

Explanation: For first-order decay, t_1/2 = ln(2)/k = 0.693/0.23 = 3.01 days. This formula appears under Reaction Kinetics and Environmental Engineering in the NCEES FE Reference Handbook.

3Eight effluent total nitrogen samples (mg/L) yielded a sample mean of 12.4 with standard deviation 2.1. What is the 95% two-sided confidence interval for the population mean (use t_0.025,7 = 2.365)?

A.12.4 ± 0.74

B.12.4 ± 1.46

C.12.4 ± 1.76

D.12.4 ± 4.97

Explanation: The CI is x̄ ± t·(s/√n) = 12.4 ± 2.365·(2.1/√8) = 12.4 ± 2.365·0.7425 = 12.4 ± 1.76 mg/L. Use the Student's t since the population variance is unknown and n is small.

4A water quality test has a 5% false-positive rate. If five independent samples are analyzed and the true value is below detection, what is the probability that at least one sample reports a false positive?

A.0.050

B.0.226

C.0.250

D.0.774

Explanation: P(at least one) = 1 − (1 − 0.05)^5 = 1 − 0.7738 = 0.2262, about 22.6%. This applies the complement rule for independent Bernoulli trials.

5Lead concentrations in drinking water are log-normally distributed. Which transformation should be applied before computing a 95th percentile assuming a normal distribution?

A.Subtract the mean from each value

B.Take the natural log of each value

C.Take the square root of each value

D.Divide each value by the standard deviation

Explanation: If X is log-normal then ln(X) is normally distributed. After log-transformation you compute percentiles using the normal table and then exponentiate the result back to the original scale. Environmental concentration data are commonly log-normal.

6Using the trapezoidal rule with two equal intervals, estimate the integral of f(x) from x = 0 to x = 4 if f(0) = 2, f(2) = 5, f(4) = 11.

A.18

B.23

C.27

D.32

Explanation: Trapezoidal rule: I = (h/2)[f0 + 2 f1 + f2] = (2/2)[2 + 2(5) + 11] = 1·23 = 23. The width h = 2 between successive x values.

7Daily flows to a wastewater plant are approximately normal with mean 12.0 MGD and standard deviation 1.5 MGD. What is the probability that flow on a randomly chosen day exceeds 14.0 MGD?

A.About 9%

B.About 16%

C.About 25%

D.About 33%

Explanation: z = (14 − 12)/1.5 = 1.33. P(Z > 1.33) ≈ 0.0918, about 9%. This kind of design-storm or peak-flow check uses the standard normal table in the NCEES FE Reference Handbook.

8Solve dC/dt = -kC for C(t) given C(0) = C0.

A.C(t) = C0 + kt

B.C(t) = C0 e^(kt)

C.C(t) = C0 e^(-kt)

D.C(t) = C0 (1 − kt)

Explanation: First-order linear ODE: separate variables to get dC/C = -k dt; integrating yields ln(C/C0) = -kt, so C(t) = C0 e^(-kt). This is the foundation of BOD decay, radioactive decay, and reactor concentration solutions.

9Chloride concentration in a river was measured monthly for one year. Which statistic best describes the typical concentration when one extreme outlier is present?

A.Arithmetic mean

B.Median

C.Range

D.Variance

Explanation: The median is robust to outliers because it depends only on rank order, while the mean is pulled toward extreme values. Environmental data with rare spikes are typically reported using the median plus an interquartile range.

10A Poisson process produces an average of 3 fish kills per decade in a watershed. What is the probability of exactly 5 fish kills in the next decade?

A.0.050

B.0.101

C.0.168

D.0.224

Explanation: P(X = 5) = e^(-λ) λ^5 / 5! with λ = 3: e^(-3) (3^5)/120 = 0.04979 · 243/120 = 0.04979 · 2.025 = 0.1008, about 10.1%.

About the FE Environmental Exam

The FE Environmental exam is one of seven NCEES Fundamentals of Engineering exams and the first step toward Professional Engineer (PE) licensure for environmental engineers. The 110-question computer-based test covers 12 areas including environmental science and chemistry, water and wastewater engineering, air quality, solid and hazardous waste, sustainability, and risk assessment. The exam is delivered year-round at Pearson VUE test centers using an on-screen searchable NCEES FE Reference Handbook.

Questions

110 scored questions

Time Limit

5 hours 20 minutes

Passing Score

Scaled (NCEES does not publish a fixed cut score)

Exam Fee

$175 (NCEES (Pearson VUE))

FE Environmental Exam Content Outline

8-12 Q

Mathematics, Probability & Statistics

Analytic geometry, calculus, ODEs, linear algebra, probability distributions, hypothesis tests, regression, and numerical methods

5-8 Q

Ethics & Professional Practice

NCEES Model Rules, public-safety paramount canon, conflicts of interest, sealing of documents, and licensure

4-6 Q

Engineering Economics

Time value of money, present/future/annual worth, benefit-cost, replacement analysis, and inflation

4-6 Q

Materials Science

Concrete (sulfate-resistant ASTM C150), corrosion (galvanic series), polymers (PVC/HDPE), and geosynthetics

11-17 Q

Environmental Science & Chemistry

Stoichiometry, pH/alkalinity/hardness, Henry's law, BOD kinetics, Monod growth, microbial ecology

5-8 Q

Risk Assessment

Hazard identification, dose-response, exposure assessment (CDI), HQ and slope-factor cancer risk per EPA paradigm

9-14 Q

Water Resources

Hydrology, rational method, Manning open-channel, Streeter-Phelps DO sag, Darcy and well hydraulics (Theis/Cooper-Jacob)

12-18 Q

Water & Wastewater Engineering

Sedimentation/SOR, filter loading, coagulation, disinfection (CT), activated sludge SRT/F:M, MBR, GAC, RO

10-15 Q

Air Quality Engineering

NAAQS criteria pollutants, Gaussian plume dispersion, AP-42 emission factors, ESP/baghouse/cyclone, SCR/FGD

9-14 Q

Solid & Hazardous Waste Engineering

RCRA Subtitle C/D/I, F/K/P/U lists, TCLP and D-codes, LDR, landfill design, leachate (HELP), USTs, remediation

4-6 Q

Sustainability

Triple Bottom Line, ISO 14040/14044 LCA, GWP / GHG inventories, LEED v4.1, cradle-to-cradle, industrial ecology

5-8 Q

Environmental Health & Safety

OSHA PELs/STELs, hierarchy of controls, noise dose, hazardous-waste manifest, EPCRA Section 313 TRI

How to Pass the FE Environmental Exam

What You Need to Know

Passing score: Scaled (NCEES does not publish a fixed cut score)
Exam length: 110 questions
Time limit: 5 hours 20 minutes
Exam fee: $175

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

FE Environmental Study Tips from Top Performers

1Master the NCEES FE Reference Handbook — every exam formula is in the PDF, so practice locating each one quickly

2Distribute study time by NCEES weighting: water/wastewater (~14%), environmental science/chemistry (~13%), and air quality (~11%) deserve the most hours

3Drill BOD kinetics, Streeter-Phelps DO sag, activated-sludge SRT/F:M, and CSTR vs PFR reactor design — they show up every exam

4Memorize core EPA regulatory thresholds: NAAQS PM2.5 = 9 µg/m³ (2024), PFOA/PFOS MCL = 4 ng/L (2024), TTHM MCL = 0.080 mg/L, lead AL = 10 µg/L (LCRI 2024)

5Practice with an NCEES-approved calculator (Casio FX-115 or TI-36X) so you do not lose time on exam day

6Review RCRA listings (F/K/P/U), TCLP D-codes, Subtitle C double-liner specs, and the Uniform Hazardous Waste Manifest workflow

7Solve at least 200 timed practice questions before scheduling — averaging about 3 minutes per question

8Review NCEES Model Rules, hierarchy of controls, OSHA noise dose, and the EPA risk paradigm (RfD, slope factor, HQ, target risk 10^-6 to 10^-4)

9Take the official NCEES FE Environmental practice exam in the final two weeks — the format mimics the real CBT interface

10Build a one-page formula cheat sheet of equations the handbook hides under multiple tabs (Streeter-Phelps, Darcy, Theis, Briggs plume rise)

Frequently Asked Questions

What is on the FE Environmental exam?

The FE Environmental exam covers 12 NCEES knowledge areas: mathematics/probability/statistics, ethics, engineering economics, materials science, environmental science and chemistry, risk assessment, water resources, water and wastewater engineering, air quality, solid and hazardous waste, sustainability, and environmental health and safety. Question counts per area come from the NCEES content specification (e.g., 12-18 questions on water and wastewater).

How long is the FE Environmental exam, and how much does it cost?

FE Environmental is a 110-question computer-based test delivered at Pearson VUE test centers. Total appointment is 5 hours 20 minutes, including a 25-minute scheduled break, an 8-minute tutorial, and a brief survey. The NCEES exam fee is $175 in 2026; some state boards add an application fee.

Can I use a calculator on the FE Environmental exam?

NCEES allows only specific calculator models: HP 33s/35s, Casio FX-115 series, and TI-30X/TI-36X series. An on-screen scientific calculator is also available. Bring backups; non-approved calculators will be confiscated at check-in.

What is the FE Environmental pass rate and how should I prepare?

First-time pass rates published by NCEES run roughly 67-74% in recent years. Plan 200-300 hours of study spread over 8-16 weeks. The single most important resource is the NCEES FE Reference Handbook — every formula on the exam is in that PDF, so you must know where each one lives.

Is FE Environmental harder than FE Civil?

The difficulty depends on background. FE Civil is broader in structures/transportation; FE Environmental is heavier on chemistry, biology, and air quality. Pass rates are comparable. Choose the discipline matching your degree, since you may select any FE discipline regardless of which PE you eventually take.

What 2026 EPA regulations should I know for FE Environmental?

Recent updates worth knowing: the 2024 PFAS NPDWR (MCLs of 4 ng/L for PFOA and PFOS), the 2024 Lead and Copper Rule Improvements (10-year LSL replacement; 10 µg/L action level), the 2024 PM2.5 NAAQS (annual primary 9 µg/m³), and EPA's 2024 methane emissions program (NSPS OOOOb/c plus the IRA Waste Emissions Charge).