Question 1

What does LARE Section 4 cover?

Accepted Answer

LARE Section 4, Grading, Drainage, and Stormwater Management, tests a landscape architect's ability to evaluate and design grading, drainage, and stormwater systems. Per the CLARB blueprint it is weighted Grading and Earthwork 44%, Stormwater Management 39%, and Drainage Systems 17%. Topics include contour grading, slope and spot-elevation calculations, ADA-compliant slopes, earthwork cut-and-fill and volume methods, the Rational Method (Q=CiA), runoff coefficients and time of concentration, detention/retention and bioretention BMPs, low impact development, pipe inverts and slopes, Manning's equation, inlets, culverts, and subsurface drains. It is the most calculation-heavy of the four LARE sections.

Question 2

How many questions are on LARE Section 4 and how long is it?

Accepted Answer

Section 4 includes approximately 70 scored items along with additional unscored pretest items that CLARB uses to evaluate future questions. The exact total number is not published. Candidates have about 3 hours of testing time within a 3.5-hour appointment. Item types include traditional multiple-choice, multiple-response (select-all-that-apply), and advanced item types such as drag-and-place and hot spot, plus quantitative earthwork and drainage calculation problems. Because the section is calculation-intensive, time management and a working knowledge of slope, volume, and runoff formulas are essential.

Question 3

What is the passing score for LARE Section 4?

Accepted Answer

CLARB sets a scaled passing score of 650 for each LARE section, including Section 4. The exam uses scaled scoring rather than a simple percentage-correct, so the number of questions you must answer correctly to reach 650 is determined through CLARB's psychometric process. Each of the four LARE sections is passed independently, and passing one section does not depend on your performance on the others. Section 4 is widely considered the most difficult section because of its heavy reliance on grading, earthwork, and stormwater calculations.

Question 4

Is LARE Section 4 the hardest section?

Accepted Answer

Many candidates consider Section 4 the most challenging LARE section because it is the most calculation-intensive, requiring fluency with slope math, earthwork volume methods, the Rational Method, and pipe hydraulics. CLARB does not publish a fixed pass rate for the section, but it is commonly reported to have among the lowest pass rates. Success depends on practicing quantitative problems under time pressure: percent-slope and ratio conversions, average end area and grid earthwork volumes, Q=CiA runoff, and computing pipe slopes from invert elevations. Conceptual knowledge of grading conventions, ADA slope limits, BMP selection, and drainage structures is equally important.

Question 5

What formulas should I know for LARE Section 4?

Accepted Answer

Key formulas include slope = rise / run (expressed as a percentage or ratio); the average end area earthwork volume V = ((A1 + A2) / 2) x L; the grid/borrow-pit method using average corner depths times the cell area; the prismoidal formula for more accurate volumes; pipe slope = (invert drop) / length; the Rational Method Q = CiA for peak runoff; and Manning's equation for open-channel and partially full pipe flow. You should also know unit conversions (27 cubic feet per cubic yard), ADA slope limits (1:12 maximum ramp running slope, 2% maximum cross slope), and minimum drainage slopes for paving (about 1%) and lawn (about 2%).

Question 6

What is the difference between a detention and a retention basin on LARE Section 4?

Accepted Answer

A detention basin temporarily stores stormwater runoff and releases it slowly through a controlled outlet so that the post-development peak discharge does not exceed allowable (often pre-development) rates; it drains dry between storms. A retention basin maintains a permanent pool of water (a wet pond) that provides storage plus water-quality treatment through settling and biological processes. Section 4 expects you to distinguish these, along with related practices like bioretention/rain gardens, constructed wetlands, permeable pavement, and low impact development, and to understand how each manages stormwater quantity, quality, or both.

Question 7

Can I take the LARE sections in any order?

Accepted Answer

Yes. CLARB administers the LARE in four independent sections, and you may take them in any order that fits your preparation and schedule. Each section is passed separately, and you only need to retake a section you do not pass. Some candidates take Section 4 last because of its calculation demands, while others tackle it early when grading and hydrology coursework is fresh. Section credit retention is subject to the time-limit rules of your licensing jurisdiction, so check with your board if you plan to spread the sections over a longer period.

Question 8

How should I prepare for LARE Section 4?

Accepted Answer

Start with the official CLARB exam blueprint to confirm the current weights (Grading and Earthwork 44%, Stormwater Management 39%, Drainage Systems 17%). Build fluency in grading math and earthwork volumes, then drill the Rational Method, time of concentration, and BMP selection, and finish with drainage hydraulics (pipe inverts, slopes, and Manning's equation). Widely used references include Site Engineering for Landscape Architects and Time-Saver Standards for Landscape Architecture. Practice quantitative problems under timed conditions, since pacing is critical, and review grading conventions, ADA slope limits, and drainage structure terminology so you can answer conceptual items quickly and leave time for calculations.

100+ Free LARE Section 4 Practice Questions

LARE Section 4: Grading, Drainage, and Stormwater Management

Explore More CLARB LARE Landscape Architect Registration

CLARB LARE Landscape Architect Registration Examination

LARE Section 1: Inventory, Analysis, and Project Management

LARE Section 2: Planning and Design

LARE Section 3: Construction Documentation and Administration

More From This Family

Key Facts: LARE Section 4 Exam

Sample LARE Section 4 Practice Questions

About the LARE Section 4 Practice Questions