100+ Free Registered Public Utility Engineer — Water Supply & Drainage Practice Questions

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2026 Statistics

Key Facts: Registered Public Utility Engineer — Water Supply & Drainage Exam

Grade-1 Licensure

National Statutory Practice Level in China

MOHURD / MOHRSS Public Utility Engineer Regulations

60%

Fixed Passing Score on Professional Subjects (120/200 and 60/100)

China Human Resources and Social Security Examination Center

GB 50013 / 50014 / 50015

Core Triad of National Water & Drainage Engineering Standards

Ministry of Housing and Urban-Rural Development

GB 50974 / 50084

Mandatory Fire Water Supply and Sprinkler Design Standards

MOHURD & Ministry of Emergency Management

3 Years

Mandatory Registration Renewal Cycle with Continuing Education

National Administration Board of Public Utility Engineering Examination

A national survey-and-design professional qualification for municipal water, wastewater, building plumbing, and fire-water systems, with Foundation and Professional examination stages.

Sample Registered Public Utility Engineer — Water Supply & Drainage Practice Questions

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1According to the Standard for Design of Outdoor Water Supply Engineering (GB 50013-2018), how is the municipal design maximum daily water demand ($Q_d$, 最高日设计用水量) calculated from the average daily water demand ($Q_a$, 平均日用水量)?

A.$Q_d = K_d \times Q_a$, where $K_d$ is the daily variation coefficient (日变化系数, typically 1.1 to 1.5)

B.$Q_d = K_h \times Q_a$, where $K_h$ is the hourly variation coefficient (时变化系数, typically 1.2 to 1.6)

C.$Q_d = (K_d + K_h) \times Q_a$, combining seasonal and diurnal variation factors

D.$Q_d = \frac{Q_a}{K_d \times K_h}$, applying peak attenuation factors

Explanation: GB 50013-2018 (Section 4.0.2) specifies that municipal water supply systems are sized on the basis of maximum daily water demand ($Q_d$). It is calculated as $Q_d = K_d \times Q_a$, where $K_d$ is the daily variation coefficient (日变化系数), reflecting seasonal, climatic, and weekly variations, typically ranging from 1.1 to 1.5 depending on city size and geographic region.

2A municipal water purification plant is designed for a maximum daily supply flow to the distribution grid of $Q_d = 100,000\text{ m}^3/\text{d}$. If the plant's internal self-consumption rate (水厂自用水率) is $8\%$, what is the required raw water design capacity of the water treatment units ($Q_{plant}$) under GB 50013-2018?

A.$92,000\text{ m}^3/\text{d}$

B.$108,000\text{ m}^3/\text{d}$

C.$116,000\text{ m}^3/\text{d}$

D.$125,000\text{ m}^3/\text{d}$

Explanation: Under GB 50013-2018 (Section 4.0.9), the design capacity of water treatment works must account for the plant's internal self-consumption rate (for filter backwashing, sludge discharge, chemical preparation, and domestic use, typically 5%–10%). $Q_{plant} = Q_d \times (1 + \alpha) = 100,000\text{ m}^3/\text{d} \times (1 + 0.08) = 108,000\text{ m}^3/\text{d}$.

3A rapid mixing tank has an effective volume of $V = 2.5\text{ m}^3$. The mechanical mixer inputs a net power of $P = 1,800\text{ W}$ into the water. At a water temperature of $20^\circ\text{C}$ (dynamic viscosity $\mu = 1.00 \times 10^{-3}\text{ Pa}\cdot\text{s}$), what is the rapid mixing velocity gradient ($G$, 速度梯度)?

A.$450\text{ s}^{-1}$

B.$600\text{ s}^{-1}$

C.$849\text{ s}^{-1}$

D.$1,200\text{ s}^{-1}$

Explanation: The Camp-Stein velocity gradient formula is $G = \sqrt{\frac{P}{\mu V}}$. Substituting the given values: $G = \sqrt{\frac{1,800\text{ W}}{(1.00 \times 10^{-3}\text{ Pa}\cdot\text{s}) \times 2.5\text{ m}^3}} = \sqrt{\frac{1,800}{0.0025}} = \sqrt{720,000} \approx 848.53\text{ s}^{-1} \approx 849\text{ s}^{-1}$. This falls squarely within the GB 50013-2018 recommended range for rapid mixing ($G = 700\text{ s}^{-1}$ to $1,000\text{ s}^{-1}$).

4Under GB 50013-2018, what is the standard design retention time (混合时间) for hydraulic rapid mixing devices (such as pipe static mixers, weir mixers, or venturi mixers)?

A.$2\text{ s}$ to $5\text{ s}$

B.$10\text{ s}$ to $30\text{ s}$

C.$2\text{ min}$ to $5\text{ min}$

D.$10\text{ min}$ to $20\text{ min}$

Explanation: GB 50013-2018 (Section 9.2.2) specifies that hydraulic rapid mixing (such as static pipe mixers, pipe orifices, and weir drops) should have a mixing duration of $10\text{ s}$ to $30\text{ s}$. Mechanical rapid mixing retention times should be between $30\text{ s}$ and $120\text{ s}$ ($0.5$ to $2.0\text{ min}$).

5A mechanical flocculation basin operates with a mean velocity gradient of $G = 40\text{ s}^{-1}$ and a hydraulic retention time of $T = 20\text{ min}$. What is the dimensionless flocculation index ($GT$ value), and does it satisfy GB 50013-2018 design guidelines?

A.$GT = 800$; below the required minimum range

B.$GT = 4.8 \times 10^4$; fully complies with the standard range ($10^4$ to $10^5$)

C.$GT = 4.8 \times 10^5$; exceeds the maximum permissible limit

D.$GT = 8.0 \times 10^5$; violates the laminar floc stability threshold

Explanation: First convert time $T$ from minutes to seconds: $T = 20\text{ min} \times 60\text{ s/min} = 1,200\text{ s}$. Then, $GT = 40\text{ s}^{-1} \times 1,200\text{ s} = 48,000 = 4.8 \times 10^4$. GB 50013-2018 (Section 9.3.1) recommends that the total $GT$ value for flocculation basins should be between $10^4$ and $10^5$, with a total retention time of $15\text{ min}$ to $30\text{ min}$. Thus, $4.8 \times 10^4$ is fully compliant.

6Why do GB 50013-2018 standards mandate 'tapered flocculation' (阶梯式絮凝), where the velocity gradient $G$ gradually decreases from the initial stage ($G_1 \approx 70\text{ s}^{-1}$) to the final stage ($G_3 \approx 15\text{–}20\text{ s}^{-1}$)?

A.To save electricity in the final stages of water treatment

B.To prevent high initial shear and increase water temperature towards the outlet

C.To maximize particle collision frequency early on while preventing hydraulic shear breakup of fragile, grown flocs later

D.To ensure that heavier coagulant precipitates sink directly to the floor of the flocculation basin

Explanation: In coagulation-flocculation kinetics, high velocity gradient $G$ in the first stage maximizes particle collision frequency (orthokinetic flocculation) when micro-flocs are tiny and resilient. As flocs aggregate and grow into larger, looser, and more shear-sensitive structures (alum/iron hydroxides), high shear stress would tear them apart. Therefore, tapering $G$ downwards ($70\text{ s}^{-1} \to 40\text{ s}^{-1} \to 15\text{–}20\text{ s}^{-1}$) promotes continued growth while preventing floc breakage.

7Under GB 50013-2018, what are the standard design criteria for horizontal flow sedimentation tanks (平流式沉淀池) regarding hydraulic retention time ($t$) and horizontal flow velocity ($v$)?

A.Retention time $t = 0.5\text{–}1.0\text{ h}$; horizontal velocity $v = 40\text{–}60\text{ mm/s}$

B.Retention time $t = 1.5\text{–}3.0\text{ h}$; horizontal velocity $v = 10\text{–}25\text{ mm/s}$

C.Retention time $t = 4.0\text{–}6.0\text{ h}$; horizontal velocity $v = 1\text{–}5\text{ mm/s}$

D.Retention time $t = 8.0\text{–}12.0\text{ h}$; horizontal velocity $v = 0.1\text{–}0.5\text{ mm/s}$

Explanation: GB 50013-2018 (Section 9.4.2) specifies that horizontal flow sedimentation tanks should have a hydraulic retention time ($t$) of $1.5\text{ h}$ to $3.0\text{ h}$, a horizontal flow velocity ($v$) of $10\text{ mm/s}$ to $25\text{ mm/s}$, and a surface overflow loading rate ($q$) of $1.2\text{–}2.5\text{ m}^3/(\text{m}^2\cdot\text{h})$.

8An inclined tube (lamella) sedimentation tank (斜管沉淀池) treats a design flow rate of $Q = 2,400\text{ m}^3/\text{h}$. If the effective plan surface area of the inclined tube zone is $A = 300\text{ m}^2$, what is the surface overflow rate ($q$), and does it comply with GB 50013-2018?

A.$q = 4.0\text{ m}^3/(\text{m}^2\cdot\text{h})$; below standard operating capacity

B.$q = 8.0\text{ m}^3/(\text{m}^2\cdot\text{h})$ ($2.22\text{ mm/s}$); fully compliant ($5.0\text{–}9.0\text{ m}^3/(\text{m}^2\cdot\text{h})$)

C.$q = 12.0\text{ m}^3/(\text{m}^2\cdot\text{h})$; exceeds permissible surface loading

D.$q = 16.0\text{ m}^3/(\text{m}^2\cdot\text{h})$; severe hydraulic overload

Explanation: The surface overflow rate is $q = \frac{Q}{A} = \frac{2,400\text{ m}^3/\text{h}}{300\text{ m}^2} = 8.0\text{ m}^3/(\text{m}^2\cdot\text{h})$. In velocity units: $8.0\text{ m/h} = \frac{8.0}{3.6}\text{ mm/s} \approx 2.22\text{ mm/s}$. GB 50013-2018 (Section 9.4.15) mandates that the surface overflow rate for inclined tube sedimentation tanks in water supply engineering should be $5.0\text{–}9.0\text{ m}^3/(\text{m}^2\cdot\text{h})$ (up to $9.0\text{–}11.0\text{ m}^3/(\text{m}^2\cdot\text{h})$ for high-density clarifiers). Thus, $8.0\text{ m}^3/(\text{m}^2\cdot\text{h})$ is compliant.

9According to Hazen's shallow tank theory (浅池理论), how does the installation of inclined tubes (with inclination angle $\theta = 60^\circ$ and tube diameter $d = 25\text{–}35\text{ mm}$) fundamentally improve sedimentation performance compared to an open settling tank?

A.By increasing turbulent mixing to promote mechanical floc agglomeration during settling

B.By drastically reducing the settling distance ($h$) and Reynolds number ($Re < 500$) while maintaining a high Froude number ($Fr > 10^{-5}$)

C.By heating the water layer through solar radiation trapped inside the honeycomb plastic matrices

D.By converting gravitational settling into centrifugal separation along the tube walls

Explanation: Hazen's shallow tank theory proves that settling efficiency is proportional to surface area and independent of tank depth. By inserting inclined tubes: (1) the settling path $h$ of particles is shortened to a few centimeters; (2) the hydraulic radius is greatly reduced, lowering the Reynolds number ($Re < 500$, ensuring strictly laminar flow); and (3) the Froude number is increased ($Fr > 10^{-5}$, enhancing hydraulic stability and eliminating short-circuiting). The $60^\circ$ angle enables continuous gravity self-sloughing of accumulated sludge.

10Under GB 50013-2018, what is the standard design filtration rate (设计滤速) for ordinary single-medium rapid sand filters (普通快滤池) under normal operating conditions?

A.$2\text{–}4\text{ m/h}$

B.$8\text{–}10\text{ m/h}$

C.$18\text{–}25\text{ m/h}$

D.$30\text{–}40\text{ m/h}$

Explanation: GB 50013-2018 (Section 9.5.3) specifies that the design filtration rate for ordinary single-layer quartz sand rapid filters under normal conditions should be $8\text{–}10\text{ m/h}$ (with a forced filtration velocity during backwash of one cell of $10\text{–}14\text{ m/h}$). For dual-media (anthracite-sand) filters, normal rates are $10\text{–}14\text{ m/h}$.

About the Registered Public Utility Engineer — Water Supply & Drainage Exam

The National Qualification Examination for Registered Public Utility Engineer — Water Supply and Drainage (全国注册公用设备工程师(给水排水)执业资格考试) is administered under the MOHURD and MOHRSS survey-and-design framework. It assesses municipal water supply, drainage and wastewater, building water systems, and fire-water engineering.

Assessment

Foundation Exam: Subject 1 Public Basic (公共基础, 120 MCQs, 120 pts) + Subject 2 Specialty Basic (专业基础, 60 MCQs, 120 pts); Professional Exam: Subject 1 Professional Knowledge (专业知识上/下, 80 single-choice + 60 multiple-choice, 200 pts) + Subject 2 Professional Case Analysis (专业案例上/下, 50 case calculation questions, 100 pts).

Time Limit

Foundation: 4.0 hours morning + 4.0 hours afternoon; Professional Knowledge: 3.0 hours morning + 3.0 hours afternoon; Professional Case Analysis: 3.0 hours morning + 3.0 hours afternoon.

Passing Score

Foundation: 132/240 points (55%); Professional Knowledge: 120/200 points (60%); Professional Case Analysis: 60/100 points (60%)

Exam Fee

Set by the provincial examination authority; consult the current registration notice (Ministry of Housing and Urban-Rural Development (MOHURD) & Ministry of Human Resources and Social Security (MOHRSS))

Registered Public Utility Engineer — Water Supply & Drainage Exam Content Outline

30%

Municipal Water Supply Engineering (室外给水工程)

Water resources planning, water demand forecasting and design flow rates (Q_d, K_d, K_h), water intake structures, coagulation and rapid mixing velocity gradient (G-value), mechanical and hydraulic flocculation (GT values), sedimentation and flotation (horizontal, inclined tube/plate surface overflow rates), rapid sand and multimedia filtration hydraulics and backwashing, disinfection kinetics (Chick-Watson law, chlorine CT values, ozone, UV), water supply transmission and distribution network hydraulics (Hardy Cross loop balancing, Colebrook-White friction), and water supply pumping stations (TDH, NPSHa, cavitation, pump curve analysis).

30%

Municipal Drainage & Wastewater Engineering (室外排水工程)

Wastewater collection systems and peaking coefficients (K_z = 1 + 2.7/Q^0.11), storm sewer design via rational method (Q = q * psi * F) and rainfall intensity formulas, sewer hydraulics via Manning equation (v = 1/n * R^(2/3) * S^(1/2)), minimum self-cleansing velocities, pipe fullness and slope limits, wastewater treatment mechanics, biological nutrient removal (A2O anaerobic phosphorus release, anoxic denitrification, aerobic nitrification, internal recycle ratio R), SBR/CAST, oxidation ditches, secondary clarifier solids loading rates (SLR), and sludge thickening, anaerobic digestion methane yield, and dewatering.

25%

Building Water Supply & Drainage Engineering (建筑给水排水工程)

Building domestic cold water systems, fixture unit probability design flow method (q_g = 0.2 * alpha * sqrt(N_g) + k * N_g), water pressure zoning criteria (static <= 0.45 MPa, dynamic <= 0.20 MPa, PRVs), domestic hot water system heating power, heat exchanger surface area, centralized solar water heating, hot water return circulation, sanitary drainage fixture units (DFU), drainage stack capacities (single-stack, special single-stack fittings, dedicated vent stacks), water trap seals (min 50 mm), and gravity/siphonic roof rainwater drainage systems.

15%

Building Fire Water Supply & Fire Suppression Systems (建筑消防给水与灭火系统)

Fire water storage pool effective volume calculation, rooftop elevated fire water tank sizing (18/36/50/100 m³), fire pump sizing, head, and suction piping, indoor/outdoor fire hydrant system pressure and flow requirements (nozzle pressure >= 0.35 MPa, water jet length >= 13 m), automatic sprinkler system hazard classifications (Light, Ordinary I/II, High Hazard), design discharge density and design area, hydraulic calculations (q = K * sqrt(10P)), deluge, pre-action, dry-pipe systems, and water mist fire extinguishing systems.

How to Pass the Registered Public Utility Engineer — Water Supply & Drainage Exam

What You Need to Know

Passing score: Foundation: 132/240 points (55%); Professional Knowledge: 120/200 points (60%); Professional Case Analysis: 60/100 points (60%)
Assessment: Foundation Exam: Subject 1 Public Basic (公共基础, 120 MCQs, 120 pts) + Subject 2 Specialty Basic (专业基础, 60 MCQs, 120 pts); Professional Exam: Subject 1 Professional Knowledge (专业知识上/下, 80 single-choice + 60 multiple-choice, 200 pts) + Subject 2 Professional Case Analysis (专业案例上/下, 50 case calculation questions, 100 pts).
Time limit: Foundation: 4.0 hours morning + 4.0 hours afternoon; Professional Knowledge: 3.0 hours morning + 3.0 hours afternoon; Professional Case Analysis: 3.0 hours morning + 3.0 hours afternoon.
Exam fee: Set by the provincial examination authority; consult the current registration notice

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Registered Public Utility Engineer — Water Supply & Drainage Study Tips from Top Performers

1Master Velocity Gradients and Flocculation GT Values: Memorize rapid mixing velocity gradient criteria (G = 700–1000 s⁻¹) and flocculation GT criteria (GT = 10⁴–10⁵ with G tapering from 70 s⁻¹ down to 15 s⁻¹) per GB 50013.

2Understand the Rational Method and Peaking Factors: Practice storm sewer design using Q = q * psi * F and rainfall intensity formulas, and apply total peaking factors (K_z = 1 + 2.7 / Q^0.11) for municipal domestic wastewater flows per GB 50014.

3Drill Manning's Open-Channel Sewer Hydraulics: Memorize pipe fullness limits (h/D <= 0.55 to 0.75), minimum self-cleansing velocity (0.6 m/s for sanitary sewers, 0.75 m/s for storm sewers), and minimum pipe diameters (300 mm for streets, 200 mm for residential quarters).

4Memorize Biological Nutrient Removal Recycle Ratios: Practice A2O internal nitrate recycle calculations (R = (TN_in - TN_e) / TN_e - 1) and solids loading rate formulas for secondary clarifiers.

5Practice Building Cold Water Design Flow Probability Method: Master the GB 50015 probability formula (q_g = 0.2 * alpha * sqrt(N_g) + k * N_g) for residential units and peak simultaneous fixture calculation for public facilities.

6Master Fire Water Storage and Hydrant Jet Calculations: Review GB 50974 fire water pool effective storage subtraction rules, fire pump suction piping design, nozzle pressure thresholds (0.35 MPa for high-rises), and elevated roof tank capacities (18, 36, 50, 100 m³).

Frequently Asked Questions

What is the Registered Public Utility Engineer (Water Supply & Drainage) qualification in China?

The Registered Public Utility Engineer — Water Supply and Drainage (注册公用设备工程师(给水排水)) is a national survey-and-design professional qualification administered under the MOHURD and MOHRSS framework.

What is the exam structure and passing standard for this credential?

The examination is divided into two major stages: Foundation Exam (基础考试) and Professional Exam (专业考试). The Foundation Exam consists of Public Basic (120 pts) and Specialty Basic (120 pts) with a passing threshold of 132/240 points. The Professional Exam is open-book and consists of Professional Knowledge (200 pts, passing score 120) and Professional Case Analysis (100 pts, passing score 60). Candidates must pass both professional subjects in the same examination year.

Which national design codes and technical standards are core to the syllabus?

The core national standards tested are: GB 50013 (Standard for Design of Outdoor Water Supply Engineering), GB 50014 (Standard for Design of Outdoor Wastewater Engineering), GB 50015 (Standard for Design of Building Water Supply and Drainage), GB 50974 (Technical Code for Fire Protection Water Supply and Hydrant Systems), and GB 50084 (Code for Design of Sprinkler Systems), along with GB 50849, GB 50898, and GB 50265.

Why is this OpenExamPrep question bank provided in English?

This is an English-language MCQ study adaptation, not an official translation or format simulation and not a substitute for open-book case-analysis work. Official Chinese terminology, GB identifiers, and formulas integral to the syllabus are retained for cross-reference.