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100+ Free Sanitary Engineer Licensure Exam Practice Questions

Prepare for the PRC Sanitary Engineer Licensure Examination (SELE) exam with instant access — no signup required.

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2026 Statistics

Key Facts: Sanitary Engineer Licensure Exam Exam

6

Board Subjects

PRC Board of Sanitary Engineering

70%

Passing Average

PRC

50%

Minimum Per Subject

PRC

270

Jan 2026 Examinees

PRC

CBLE

Computer-Based

PRC 2026

RA 1364

Governing Law

Sanitary Engineering Law

The Sanitary Engineer Licensure Examination (SELE) is the PRC objective board exam for registration under RA 1364, now delivered as a computer-based licensure examination (CBLE). Candidates must obtain a 70% weighted general average with no grade below 50%. The January 2026 CBLE had 270 examinees with results released immediately after testing. Coverage spans six subjects: Water Supply, Wastewater and Urban Drainage, Environmental Engineering, Sanitary Science as Applied to Buildings, Public Health Engineering, and allied Civil Engineering, with about a 70% objective and 30% problem-solving split.

Sample Sanitary Engineer Licensure Exam Practice Questions

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

1In the conventional water treatment train, chemical coagulants such as alum are added during which unit process to destabilize colloidal particles?
A.Slow flocculation
B.Rapid mixing (coagulation)
C.Sedimentation
D.Disinfection
Explanation: Coagulant chemicals like aluminum sulfate (alum) are introduced and dispersed during rapid mixing so the resulting metal hydroxides neutralize the negative surface charge of colloids, allowing them to agglomerate. This destabilization step must occur before gentle flocculation builds settleable floc.
2A surface water source is to supply a community of 50,000 people at an average rate of 150 liters per capita per day (lpcd). What is the average daily demand in cubic meters per day?
A.3,750 m3/day
B.750 m3/day
C.75,000 m3/day
D.7,500 m3/day
Explanation: Average daily demand equals population multiplied by per-capita demand: 50,000 persons x 150 L/person/day = 7,500,000 L/day. Dividing by 1,000 L/m3 gives 7,500 m3/day. Per-capita demand multiplied by population is the standard basis for sizing water supply works.
3Which Philippine law is the principal statute regulating the practice of sanitary engineering and creating the Board of Sanitary Engineering?
A.Republic Act No. 1364
B.Presidential Decree No. 856
C.Republic Act No. 9275
D.Republic Act No. 9003
Explanation: Republic Act No. 1364 is the Sanitary Engineering Law; it regulates the practice of sanitary engineering in the Philippines and created the Board of Examiners (now the Professional Regulatory Board) for Sanitary Engineering. The licensure examination is administered under this act.
4Free residual chlorine is generally preferred over combined chlorine (chloramines) for primary disinfection of drinking water mainly because free chlorine is:
A.A weaker oxidant requiring longer contact
B.Incapable of inactivating viruses
C.A more powerful and faster-acting disinfectant
D.Only effective above pH 9
Explanation: Free residual chlorine (hypochlorous acid and hypochlorite ion) is a stronger, faster-acting disinfectant than combined chlorine, achieving the required CT (concentration x time) more quickly. Chloramines act more slowly and are typically used to maintain a stable residual in the distribution system rather than for primary kill.
5A rectangular sedimentation basin treats 4,320 m3/day with a surface area of 180 m2. What is the surface overflow rate (surface loading rate)?
A.24 m3/m2/day
B.12 m3/m2/day
C.8 m3/m2/day
D.240 m3/m2/day
Explanation: Surface overflow rate equals flow divided by plan surface area: 4,320 m3/day / 180 m2 = 24 m3/m2/day. This loading rate, equivalent to the settling (critical) velocity, governs which particles are captured; typical design values for plain settling fall well within this range.
6Hardness in water is primarily caused by the presence of dissolved:
A.Calcium and magnesium ions
B.Sodium and potassium ions
C.Chloride and sulfate ions
D.Iron and manganese only
Explanation: Hardness is caused mainly by polyvalent cations, predominantly calcium (Ca2+) and magnesium (Mg2+). It is usually expressed as mg/L of equivalent CaCO3 and causes scaling and excessive soap consumption, which is why softening removes these ions.
7In a rapid sand filter, the process used to remove accumulated solids and restore filter capacity is called:
A.Flocculation
B.Aeration
C.Backwashing
D.Coagulation
Explanation: Backwashing reverses the flow upward through the sand bed at a velocity high enough to fluidize the media, dislodging trapped solids that are carried to waste. Rapid sand filters are backwashed periodically when head loss becomes excessive or effluent quality declines.
8The ratio of the maximum day demand to the average day demand for a municipal water system is commonly assumed to be about:
A.1.5 to 1.8
B.1.0
C.0.5
D.5.0
Explanation: Peaking factors account for demand variation; the maximum-day to average-day ratio is typically taken as roughly 1.5 to 1.8 in design practice. Treatment plants are often sized for maximum-day demand, while distribution mains and pumps consider the higher peak-hour factor.
9Water flows through a 0.30 m diameter pipe at a velocity of 2.0 m/s. What is the volumetric flow rate?
A.0.071 m3/s
B.0.566 m3/s
C.0.018 m3/s
D.0.141 m3/s
Explanation: Flow rate Q equals velocity times cross-sectional area: A = (pi/4)(0.30)^2 = 0.0707 m2, so Q = 2.0 x 0.0707 = 0.141 m3/s. The continuity equation Q = AV is fundamental for sizing pipes and channels in water supply.
10Under Philippine drinking-water standards, the most important microbiological indicator organism whose absence signals the likely absence of fecal contamination is:
A.Total dissolved solids
B.Escherichia coli / thermotolerant coliforms
C.Pseudomonas aeruginosa
D.Algae
Explanation: Thermotolerant (fecal) coliforms, especially Escherichia coli, are the standard indicator organisms for fecal contamination of drinking water. Their absence in a sample strongly suggests the water is free of recent fecal pollution, which is why potable water standards require zero E. coli per 100 mL.

About the Sanitary Engineer Licensure Exam Exam

The PRC Sanitary Engineer Licensure Examination (SELE) is the objective board examination required to become a registered sanitary engineer in the Philippines under Republic Act No. 1364. Now fully computerized, the examination covers six board subjects: Water Supply Engineering, Wastewater and Urban Drainage Engineering, Environmental Engineering, Sanitary Science as Applied to Buildings (plumbing), Public Health Engineering, and allied Civil Engineering. It tests both conceptual knowledge and problem-solving across water and wastewater treatment, sanitation, plumbing codes, and Philippine environmental and sanitation laws.

Assessment

Question count not published by the exam provider

Time Limit

Multi-day computer-based licensure examination

Passing Score

70% weighted general average, no grade below 50%

Exam Fee

PRC examination fee (verify current PRC schedule) (Professional Regulation Commission (PRC) - Board of Sanitary Engineering)

Sanitary Engineer Licensure Exam Exam Content Outline

18%

Water Supply Engineering

Sources, demand, coagulation, sedimentation, filtration, disinfection, softening, and distribution

18%

Wastewater and Urban Drainage Engineering

Sewerage, sewer hydraulics, activated sludge, trickling filters, sludge handling, and disposal

18%

Environmental Engineering

Air and water pollution control, solid waste management, and Philippine environmental laws

18%

Sanitary Science as Applied to Buildings

Plumbing systems, Revised National Plumbing Code, traps, vents, fixture units, backflow prevention

18%

Public Health Engineering

Disease transmission, environmental sanitation, excreta disposal, food and water safety, PD 856

10%

Civil Engineering (Allied)

Mathematics, hydraulics, structural and materials fundamentals, and construction management

How to Pass the Sanitary Engineer Licensure Exam Exam

What You Need to Know

  • Passing score: 70% weighted general average, no grade below 50%
  • Assessment: Question count not published by the exam provider
  • Time limit: Multi-day computer-based licensure examination
  • Exam fee: PRC examination fee (verify current PRC schedule)

Keys to Passing

  • Work through all 100 available questions
  • Review every answer and explanation
  • Track weak areas and revisit them
  • Use our AI tutor for tough concepts

Sanitary Engineer Licensure Exam Study Tips from Top Performers

1Allocate review time by subject weight - five subjects at about 18% and Civil Engineering at about 10%
2Master water and wastewater treatment unit processes and their typical design parameters
3Memorize key Plumbing Code rules: trap seal 51-102 mm, prohibited S-traps, venting, and fixture units
4Know the major laws: RA 1364, PD 856, the Revised National Plumbing Code, RA 9275, RA 8749, and RA 9003
5Practice computations for flow, BOD load, removal efficiency, detention time, and overflow rate
6Review hydraulics fundamentals such as continuity, Manning's equation, and head loss
7Study public-health concepts: waterborne diseases, vector control, and environmental sanitation
8Take timed objective practice sets to sharpen pacing for the computer-based format

Frequently Asked Questions

What is the passing score for the sanitary engineer board exam?

To pass the Sanitary Engineer Licensure Examination, a candidate must obtain a weighted general average of at least 70% with no grade below 50% in any of the board subjects. The exam is now a computer-based licensure examination administered by the PRC Board of Sanitary Engineering.

What subjects are covered in the SELE?

The exam covers six board subjects: Water Supply Engineering, Wastewater and Urban Drainage Engineering, Environmental Engineering, Sanitary Science as Applied to Buildings (plumbing), Public Health Engineering, and allied Civil Engineering. Five of these are weighted at about 18% each and Civil Engineering at about 10%.

Is the sanitary engineer board exam computerized?

Yes. The PRC has transitioned the Sanitary Engineer Licensure Examination to a computer-based licensure examination (CBLE). The January 2026 administration was fully computerized, and results were released immediately after the examination, with 270 examinees.

What law governs sanitary engineering practice in the Philippines?

Republic Act No. 1364, the Sanitary Engineering Law, regulates the practice of sanitary engineering and created the Board of Sanitary Engineering. Related statutes commonly tested include PD 856 (Code on Sanitation), the Revised National Plumbing Code, RA 9275 (Clean Water Act), RA 8749 (Clean Air Act), and RA 9003 (Solid Waste Management Act).

Who is eligible to take the sanitary engineer board exam?

Applicants must be Filipino citizens (or qualified reciprocity applicants) of good moral character who hold a Bachelor of Science in Sanitary Engineering from a recognized program. Candidates file the PRC application and submit required documents before the examination.

How should I prepare for the SELE?

Allocate review time by subject weight, mastering water supply and wastewater treatment, environmental engineering, plumbing-code provisions, and public-health sanitation. Study the key Philippine laws and codes, practice computational hydraulics and treatment problems, and take timed objective practice sets to build speed and accuracy.