Is the PE Civil Water Resources exam all water engineering?

No, and the gap is larger than the name suggests. Four of the twelve areas are not water or environmental engineering at all - Project Sitework, Materials, Project Planning and Soil Mechanics - and by the specification's own ranges they account for 20 to 31 of the 80 questions. Project Sitework alone is the single largest knowledge area on the exam, larger than Hydrology. A candidate who prepares only hydraulics, hydrology and treatment leaves roughly a quarter to a third of the paper uncovered.

How long is the PE Civil exam and how many questions?

Eighty questions in a 9-hour appointment, of which 8 hours is exam time. Across 80 questions that is 6 minutes each, which is our own arithmetic rather than a figure NCEES publishes - and it is roughly double the working time per question the FE allows, because PE questions are longer and more design-like rather than because they are more generous.

Is the PE Civil Water Resources specification changing?

Yes. The specification effective April 2024 runs through the March 2027 administrations. NCEES has already published a revised design-standards specification that takes effect with the April 2027 examination. If you are sitting in 2026 or early 2027 the current specification applies; if you are buying prep material now for a sitting after that date, check which specification it was written against, because the design standards are what changed.

What reference material do you get on the PE Civil exam?

The exam is closed book with an on-screen searchable reference: the NCEES PE Civil Reference Handbook, together with the design standards the specification lists - for the Water Resources and Environmental depth that includes the Ten States Standards for water and wastewater. You cannot bring your own copy. Practising against the searchable PDF rather than a printed copy matters more than candidates expect, because locating an equation under time pressure is a distinct skill from knowing it.

PE Civil Water Resources: what the exam actually covers

The largest single knowledge area on the PE Civil Water Resources and Environmental exam is Project Sitework — excavation, grading, retaining walls, construction methods. It is bigger than Hydrology. It is bigger than either hydraulics block. Read the NCEES specification by family rather than by row and between 20 and 31 of the 80 questions turn out not to be water engineering at all.

Updated September 1, 2026 · by the FE to PE Prep team

Questions

Exam time

Knowledge areas

~6 min

Per question

The exam is named for a quarter of itself

Eight of the twelve areas are water and environmental engineering, and together they carry between 50 and 77 questions. The other four — Project Sitework, Materials, Project Planning and Soil Mechanics — carry between 20 and 31. That is a construction-engineering block, a geotechnical block, and a project-management block, sitting inside a depth exam most candidates prepare for as though it were hydraulics and treatment.

Project Sitework is the biggest area on the paper. Nine to fourteen questions on grading and cut-and-fill, site layout, erosion and sediment control, safety, curve elements, retaining walls and construction methods. Only the erosion and sediment control is environmental in any real sense.
Soil Mechanics and Materials are eight to twelve more. Lateral earth pressure, consolidation, bearing capacity, settlement, slope stability, soil classification and boring logs, concrete, piping materials. That is a geotechnical exam in miniature, and it is worth as much as Drinking Water Distribution and Treatment.
Project Planning is four to six. Quantity take-off, cost estimating, schedules, sequencing, present worth and lifecycle comparison — the same material an estimator uses, and none of it in the reference handbook's hydraulics chapters.
It is six minutes a question, not three. Eight hours of exam time across 80 questions, which is double the FE's pace. That is not generosity: PE questions are longer, more design-like, and expect fluent movement between the handbook and the design standards.

Three real problems

One from Project Sitework, one from Soil Mechanics, one from Open-Channel Hydraulics — so two of the three are from the areas this exam is not named after, which is the point. All drawn from our free PE Civil Water Resources set. Read the distractor notes rather than just the answer: on this exam the wrong options are engineered, not random.

1. Borrow volume for an embankment

Project Sitework is the largest knowledge area on this exam — 9 to 14 of the 80 questions, more than Hydrology and more than either hydraulics block. This is one of them, and there is not a drop of water in it.

1
medium
A. Earthwork, curves & retaining sitework
An embankment for a detention-basin berm requires 12,000 CY of compacted (in-place) fill. The borrow soil has a shrinkage of 18% (compacted volume = bank volume × (1 − shrinkage)). The bank (in-situ) volume that must be excavated from borrow is most nearly:
1. 14200 CY
2. 9840 CY
3. 14600 CY
4. 12000 CY
Show the answer & worked solution
Answer: C.14600 CY
Bank $=\dfrac{\text{compacted}}{1-\text{shrinkage}}=\dfrac{12000}{1-0.18}=14634$ CY. Distractors: MULTIPLIED by $(1-s)$ instead of dividing (9840 CY, the wrong direction — this gives a bank volume smaller than the fill); applied $(1+s)$ as if it were a SWELL factor (14160 CY); and IGNORED shrinkage altogether (12000 CY).

What the distractors teach: Every wrong answer is the same 18% applied wrongly. 9,840 CY multiplies by (1 − s) instead of dividing, which returns less borrow than the fill it has to produce — physically backwards, since compaction always consumes more bank volume than it places. 14,160 CY applies (1 + s) as though shrinkage were a swell factor; swell describes the loose volume of soil after you dig it, shrinkage the compacted volume after you place it, and that answer lands within 3% of the correct one. 12,000 CY ignores the 18% altogether. One number, three ways to misread it.

2. Terzaghi bearing capacity for a strip footing

Soil Mechanics is the smallest area on the exam at 3 to 5 questions — and it is still geotechnical engineering, on an exam named for water. Three terms in the equation, three chances to lose the mark.

2
medium
A. Lateral earth pressure & bearing capacity
A continuous (strip) footing of width $B=6\,\text{ft}$ is founded at depth $D_f=4\,\text{ft}$ in soil with cohesion $c=500\,\text{psf}$ and unit weight $\gamma=120\,\text{pcf}$ (same above and below the base, no water). The Terzaghi bearing-capacity factors are $N_c=37.2$ , $N_q=22.5$ , $N_\gamma=19.7$ . The ultimate (gross) bearing capacity $q_{ult}$ is most nearly:
1. 25700 psf
2. 39500 psf
3. 36500 psf
4. 43600 psf
Show the answer & worked solution
Answer: C.36500 psf
$q_{ult}=cN_c+\gamma D_f N_q+\tfrac12\gamma B N_\gamma=500(37.2)+120(4)(22.5)+\tfrac12(120)(6)(19.7)=18600+10800+7090=36500$ psf. Distractors: DROPPED the ½ on the $\gamma B N_\gamma$ term ( $43600$ ); SWAPPED $B$ and $D_f$ between the $N_q$ and $N_\gamma$ terms ( $39500$ ); and omitted the $\gamma D_f N_q$ surcharge term, reporting a net-like value ( $25700$ ).

What the distractors teach: The equation is right in all four options; only the handling of one term differs. 43,600 psf drops the ½ on the ½γBN_γ term, the most common Terzaghi slip there is, and it inflates the answer by 19%. 39,500 psf swaps B and D_f between the N_q and N_γ terms — easy to do, because both are lengths and both multiply γ. 25,700 psf omits the γD_fN_q surcharge entirely, which quietly answers a net bearing capacity when the question asked for gross. Checking your arithmetic finds none of these.

3. Uniform discharge in a trapezoidal channel

Open-channel hydraulics is 7 to 11 questions and Manning is its workhorse. The equation is printed for you in the handbook. The geometry is not.

3
medium
A. Uniform flow, specific energy & critical depth
An earthen trapezoidal irrigation canal has a bottom width $b=4\,\text{m}$ , side slopes $z=2$ (H:V), and runs at a normal depth $y=1.5\,\text{m}$ on a slope $S=0.0008$ with Manning $n=0.025$ . Using $Q=\frac{1}{n}AR^{2/3}S^{1/2}$ , the uniform discharge is most nearly:
1. 11.7 m³/s
2. 4.61 m³/s
3. 15.6 m³/s
4. 0.293 m³/s
Show the answer & worked solution
Answer: A.11.7 m³/s
$A=(b+zy)y=(4+2\cdot1.5)1.5=10.5$ , $P=b+2y\sqrt{1+z^2}=4+2(1.5)\sqrt{1+2^2}=10.708$ m, $R=0.981$ . $Q=\frac{1}{0.025}(10.5)(0.981)^{2/3}(0.0008)^{1/2}=11.7$ m³/s. Distractors: used the RECTANGLE area $b y$ , dropping the side triangles ( $4.61$ ); used $P=b+2y$ , omitting $\sqrt{1+z^2}$ on the slanted sides ( $15.6$ ); and dropped the conveyance constant, computing $AR^{2/3}\sqrt{S}$ without $\frac{1}{n}$ ( $0.293$ ).

What the distractors teach: Not one wrong answer misuses Manning's equation — they all misdescribe the channel. 4.61 m³/s uses the rectangle b·y and discards the two side triangles, which on a 2:1 side slope are 4.5 of the 10.5 m² of flow area: 43% of the section, thrown away. 15.6 m³/s takes P = b + 2y, measuring the sloped sides as if they were vertical, when the wetted perimeter runs along the real slope at y√(1+z²) each. 0.293 m³/s drops the 1/n conveyance factor. The difficulty in an open-channel question is almost never the equation.

Where the 80 questions come from

NCEES publishes exactly how many questions come from each knowledge area. It is the most useful study document most candidates never open. The ranges are wide and sum to between 70 and 108 across the twelve areas against an exam of 80, so no single sitting hits every maximum — but the ordering is stable, and it tells you where your hours belong.

PE Civil Water Resources and Environmental knowledge areas and question counts, per the NCEES specification effective April 2024
Knowledge area	Questions
Project Siteworknot waterThe largest area on the exam. Excavation and embankment, site layout and control, erosion and sediment control, impact on adjacent facilities, safety, horizontal and vertical curve elements, retaining walls, construction methods. Erosion and sediment control is genuinely environmental; the rest is construction engineering.	9–14
HydrologyStorm characteristics, Rational and SCS/NRCS runoff, hydrograph development including synthetic hydrographs, intensity–duration–frequency, time of concentration, gauging, depletions, and stormwater management.	8–12
Hydraulics — Closed ConduitEnergy and continuity, pressure conduit with Hazen-Williams and Darcy-Weisbach, major and minor losses, pumps including wet wells and cavitation, and pipe network analysis.	7–11
Hydraulics — Open ChannelOpen-channel flow, hydraulic grade lines and energy dissipation, stormwater collection and drainage, culverts and gutter flow, and sub- versus supercritical flow.	7–11
Wastewater Collection and TreatmentCollection systems and lift stations, preliminary through secondary treatment, nutrient removal, solids handling and disposal, disinfection, and advanced treatment.	7–11
Analysis and DesignMass balance, hydraulic loading, solids loading, and hydraulic flow measurement — the process arithmetic that sits underneath both treatment areas.	6–9
Drinking Water Distribution and TreatmentDemand and storage, distribution systems, and the treatment train through to disinfection and residuals.	6–9
Surface Water and Groundwater QualityStream degradation and oxygen dynamics, total maximum daily load, and biological and chemical contaminants.	5–8
Groundwater and WellsAquifer behaviour, well hydraulics and drawdown, and groundwater transport.	4–6
Materialsnot waterSoil classification and boring logs, soil strength and permeability and phase relations, concrete, piping materials, and test methods with specification conformance.	4–6
Project Planningnot waterQuantity take-off, cost estimating, schedules, activity sequencing, and economic and lifecycle analysis. Project management, not hydraulics.	4–6
Soil Mechanicsnot waterLateral earth pressure, consolidation and compaction, bearing capacity, settlement, slope stability. The smallest area, and pure geotechnical engineering.	3–5

Areas and ranges are NCEES's, verbatim. The “not water” tag is our own reading of the published subtopics, not an NCEES label.

Read that table by family. The eight water and environmental areas start at 50 questions between them and run to 77. The four that are not — Project Sitework, Materials, Project Planning, Soil Mechanics — start at 20 and run to 31. On an 80-question paper that is a quarter to well over a third of your marks sitting outside the subject on the exam's own title, and it is the allocation mistake worth avoiding: a water engineer revising water is under-preparing for the largest single area on the exam.

The specification changes in April 2027

The specification described on this page took effect in April 2024 and runs through the March 2027 administrations. NCEES has already published the revision that replaces it, effective with the April 2027 examination, and what changed is the design standards the exam is written against.

That matters if you are buying prep material now for a later sitting. A question bank or review course assembled against the current standards is correct for every administration up to March 2027 and progressively less so after it. Check which specification any material names before you pay for access that runs past that date — including ours.

Common questions

What is on the PE Civil Water Resources and Environmental exam?: Eighty questions drawn from twelve knowledge areas. By the NCEES specification the allocation is 9-14 questions to Project Sitework; 8-12 to Hydrology; 7-11 each to Closed-Conduit Hydraulics, Open-Channel Hydraulics, and Wastewater Collection and Treatment; 6-9 each to Analysis and Design and to Drinking Water Distribution and Treatment; 5-8 to Surface Water and Groundwater Quality; 4-6 each to Groundwater and Wells, Materials, and Project Planning; and 3-5 to Soil Mechanics. The ranges are wide on purpose - they sum to between 70 and 108 against an exam of 80, so no sitting hits every maximum.
Is the PE Civil Water Resources exam all water engineering?: No, and the gap is larger than the name suggests. Four of the twelve areas are not water or environmental engineering at all - Project Sitework, Materials, Project Planning and Soil Mechanics - and by the specification's own ranges they account for 20 to 31 of the 80 questions. Project Sitework alone is the single largest knowledge area on the exam, larger than Hydrology. A candidate who prepares only hydraulics, hydrology and treatment leaves roughly a quarter to a third of the paper uncovered.
How long is the PE Civil exam and how many questions?: Eighty questions in a 9-hour appointment, of which 8 hours is exam time. Across 80 questions that is 6 minutes each, which is our own arithmetic rather than a figure NCEES publishes - and it is roughly double the working time per question the FE allows, because PE questions are longer and more design-like rather than because they are more generous.
Is the PE Civil Water Resources specification changing?: Yes. The specification effective April 2024 runs through the March 2027 administrations. NCEES has already published a revised design-standards specification that takes effect with the April 2027 examination. If you are sitting in 2026 or early 2027 the current specification applies; if you are buying prep material now for a sitting after that date, check which specification it was written against, because the design standards are what changed.
What reference material do you get on the PE Civil exam?: The exam is closed book with an on-screen searchable reference: the NCEES PE Civil Reference Handbook, together with the design standards the specification lists - for the Water Resources and Environmental depth that includes the Ten States Standards for water and wastewater. You cannot bring your own copy. Practising against the searchable PDF rather than a printed copy matters more than candidates expect, because locating an equation under time pressure is a distinct skill from knowing it.

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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.

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Ten free PE Civil Water Resources problems in total — Rational-method peak flow, Hazen-Williams head loss, BOD removal, peaking factors, seepage velocity, degree of saturation, a phosphorus TMDL — every one with the full worked solution. No signup.

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Knowledge areas, question counts, format and the April 2027 revision are from the NCEES PE Civil: Water Resources and Environmental CBT exam specification effective beginning April 2024. The per-question time and the water / not-water split of the twelve areas are our own, not NCEES figures. No pass rate or exam fee is quoted here because we hold no primary source for either. Specifications and fees change over time — confirm current specifics at ncees.org. Independent study resource; not affiliated with, endorsed by, or sponsored by NCEES.