How to Search PE Civil WRE Reference Documents During the Exam

The PE Civil Water Resources & Environmental exam gives you a leaner reference library than most other PE Civil depths. Where Transportation examinees juggle AASHTO manuals and the MUTCD, and Structural candidates navigate ACI, AISC, and NDS codes, WRE examinees work primarily from the NCEES PE Civil Reference Handbook supplemented by the Ten States Standards. That simplicity is a genuine advantage — if you know where to find what you need.

This guide covers every reference document you’ll have access to, how the searchable PDF viewer works, and the search strategies that save the most time on exam day.

What Reference Documents Does NCEES Provide for the PE WRE Exam?

NCEES provides three reference documents for the PE Civil WRE exam, all in searchable PDF format on your exam computer:

Document	What It Covers	When You’ll Use It
PE Civil Reference Handbook	Formulas, tables, and constants for hydraulics, hydrology, water/wastewater treatment, geotechnical, and environmental engineering	Most questions — this is your primary reference for 70–80% of the exam
Recommended Standards for Water Works (Ten States Standards — Drinking Water)	Design criteria for water treatment plants, distribution systems, intake structures, pumping stations, storage facilities	Drinking water treatment and distribution design questions
Recommended Standards for Wastewater Facilities (Ten States Standards — Wastewater)	Design criteria for wastewater collection systems, treatment plants, sludge handling, disinfection	Wastewater collection and treatment facility design questions

That’s it — three documents total. Compare this to the PE Civil Transportation depth, which provides the PE Civil Reference Handbook plus the AASHTO Green Book, Highway Capacity Manual, MUTCD, and other standards. The WRE reference set is significantly smaller, and that works in your favor.

How Does the Searchable PDF Viewer Work During the Exam?

The PE exam is administered at Pearson VUE testing centers on a computer with a split-screen interface. Your questions appear on one side, and the reference documents appear on the other. Here is how the reference viewer works:

• Chapter-by-chapter navigation: You select a document from the reference panel, then navigate to a specific chapter or section using the table of contents. You can only view one chapter at a time.
• Ctrl+F search within chapters: Once you have a chapter open, you can use Ctrl+F to search for keywords within that chapter. The search does not span across chapters — you must be in the right chapter first.
• No cross-document search: You cannot search across all three documents simultaneously. You choose a document, choose a chapter, then search within it.
• Scrolling and zooming: Standard PDF controls for scrolling through pages and zooming in on tables or figures.

Why Does the PE WRE Exam Have Fewer Reference Documents?

The WRE depth is fundamentally more formula-driven than code-driven. Consider the difference:

• Structural engineers need ACI 318, AISC Steel Manual, NDS, and ASCE 7 because every beam, column, and connection must comply with specific code provisions and load combinations. The codes are the work.
• Transportation engineers need the AASHTO Green Book for geometric design, the HCM for level-of-service analysis, and the MUTCD for signing and marking — each with its own tables and lookup procedures.
• WRE engineers rely on universal hydraulics and hydrology formulas that apply broadly across problems. Manning’s equation works the same way whether you’re sizing a storm sewer or analyzing a natural channel. The PE Civil Reference Handbook captures these formulas in one place.

The Ten States Standards fill the gap for facility design criteria — detention times, loading rates, disinfection requirements — that are not purely formula-based. But the bulk of WRE problem-solving comes from applying well-known equations, and those equations live in the PE Civil Reference Handbook.

This is an advantage. Fewer documents means less time switching between references, less confusion about where to look, and more time solving problems.

How Do You Navigate the PE Civil Reference Handbook for WRE Questions?

The PE Civil Reference Handbook is organized by engineering discipline. For WRE, you’ll spend most of your time in the hydraulics, hydrology, and environmental sections. Here is a map of where to find the formulas you need most:

Hydraulics (Open Channel and Closed Conduit)

• Manning’s equation — normal depth, partially full pipe flow, roughness coefficients \[ Q = \frac{1.49}{n}\, A\, R^{2/3}\, S^{1/2} \] where \( R = A/P \) (hydraulic radius)
• Hazen-Williams formula — pressure pipe flow, C-values for common pipe materials \[ V = 1.318\, C\, R_h^{0.63}\, S^{0.54} \] Head loss form: \( h_f = \dfrac{10.67\, L\, Q^{1.852}}{C^{1.852}\, D^{4.87}} \)
• Bernoulli’s equation — energy grade line, hydraulic grade line \[ \frac{P_1}{\gamma} + \frac{V_1^2}{2g} + z_1 = \frac{P_2}{\gamma} + \frac{V_2^2}{2g} + z_2 + h_L \]
• Darcy-Weisbach equation and Moody diagram — friction losses in pressure pipe
• Weir and orifice equations — sharp-crested weirs, broad-crested weirs, submerged orifice flow
• Specific energy and critical depth — Froude number, hydraulic jump conjugate depths
• Pump affinity laws and NPSH calculations

Hydrology

• Rational Method — peak flow for small watersheds \[ Q = CiA \]
• SCS/NRCS Curve Number method — runoff depth, S and CN relationships \[ Q = \frac{(P - 0.2S)^2}{P + 0.8S} \quad\text{where}\quad S = \frac{1000}{CN} - 10 \]
• Unit hydrograph methods — SCS dimensionless unit hydrograph, convolution
• Time of concentration estimates — Kirpich, TR-55 methods
  SCS lag method: \( T_c = \dfrac{L^{0.8}(S+1)^{0.7}}{1140 \cdot Y^{0.5}} \)
• Flood frequency analysis — Log-Pearson Type III, return periods, exceedance probability
• Hydrograph routing — Muskingum method parameters

Water Treatment

• Settling velocity — Stokes’ law, overflow rate \[ v_s = \frac{g(\rho_s - \rho)\,d^2}{18\mu} \]
• Filtration — loading rates, backwash calculations
• Disinfection — CT concept, chlorine demand and residual
• Coagulation/flocculation — mixing intensity (G values), detention time

Wastewater Treatment

• BOD kinetics — first-order decay, ultimate BOD, BOD removal efficiency \[ BOD_t = L_0(1 - e^{-kt}) \]
• Activated sludge — F:M ratio, SRT, MLSS, return sludge calculations
  Solids retention time: \( \theta_c = \dfrac{V \cdot X}{Q_w \cdot X_r} \)
• Nitrification/denitrification — oxygen demand, alkalinity consumption
• Mass balance — mass loading (8.34 factor for US customary units)
• Clarifier design — overflow rate, solids loading rate

What Topics Are Covered in the Ten States Standards?

The Ten States Standards are two separate documents, each focused on facility design criteria. They provide specific numerical standards that the PE Civil Reference Handbook does not contain.

Recommended Standards for Water Works (Drinking Water)

• Source development — well construction, surface water intake design
• Treatment plant design — flocculation detention times, sedimentation basin overflow rates, filter loading rates
• Disinfection requirements — contact time requirements, backup disinfection systems
• Distribution system — minimum pipe sizes (typically 6” for mains, 8” for fire flow), minimum pressures (20 psi minimum, 35 psi normal operating), separation distances from sanitary sewers
• Storage — finished water storage requirements, overflow and venting, security
• Pumping stations — design flow rates, backup power requirements

Recommended Standards for Wastewater Facilities

• Collection systems — minimum pipe sizes (8” for gravity sewers), minimum slopes for self-cleansing velocity, manhole spacing
• Lift stations — wet well sizing, pump selection, alarm systems, backup power
• Treatment plant design — design flow calculations (average, peak, minimum), peaking factors
• Primary treatment — sedimentation basin sizing, surface overflow rates
• Secondary treatment — activated sludge loading rates, aeration requirements, clarifier design criteria
• Sludge handling — digester sizing, dewatering requirements
• Disinfection — chlorination requirements, dechlorination, UV disinfection criteria

What Are the Most Common Search Mistakes on the PE WRE Exam?

Which Formulas Should You Memorize vs. Look Up?

The PE WRE exam rewards formula fluency. Because the PE Civil Reference Handbook is your primary reference and most WRE problems are formula-driven, knowing the core equations by heart gives you a significant speed advantage.

The dividing line is frequency of use. Any formula that appears in three or more questions per exam session is worth memorizing. Anything used once or that involves specific constants you might misremember is safer to look up.

How Can You Practice Searching Reference Documents Before Exam Day?

The best way to build reference-search fluency is to practice under realistic conditions:

1. Download the PE Civil Reference Handbook from NCEES. It is available as a free PDF on the NCEES website. Open it and get familiar with the table of contents, chapter organization, and major section headings.
2. Review the Ten States Standards. These are also available online. Read through the table of contents for both the water works and wastewater facilities documents so you know their structure.
3. Practice timed lookups. Give yourself a question, start a timer, and find the relevant formula or design criterion. Your goal is under 30 seconds for handbook formulas and under 60 seconds for Ten States Standards criteria.
4. Build a reference map. During your study period, create a one-page cheat sheet mapping each major topic to its location in the reference documents. You cannot bring this into the exam, but the act of creating it builds the mental map you need.
5. Take practice exams with the PDF open. When you solve practice problems, use only the official reference documents — not your study notes. This trains you to find information under time pressure.

Frequently Asked Questions