Water Math Practice Problems
Calculations run through every water operator exam: WPI says 9 to 11 percent of its Class I and II water exams are calculation items, and California’s outlines list them in every category.
100 questions across the published subjects, with a score for every area and an explanation for every option.
Or try the free water math drill- 45 original water math questions, every option explained
- Tested on 16 of our 25 practice exams
The pump in a station delivers 26.5 water horsepower at 75% pump efficiency. What brake horsepower must the motor supply?
What our water math questions cover
- Unit conversions: gpm, gpd and MGD; mg/L and µg/L; psi and feet
- Volume of tanks, basins, wells and pipe; detention time
- Pounds formula, chlorine demand and residual, hypochlorite and fluoride feed
- CT and T10, filtration, backwash and unit filter run volume
- Velocity, flow, total head and water horsepower
This list is our own summary, written for practice. The exam owners publish their outlines: California’s Expected Range of Knowledge, TCEQ’s Need-to-Know Criteria and WPI’s Need-to-Know Criteria.
Drill water math, then sit a full practice exam
100 questions across the published subjects, with a score for every area and an explanation for every option.
Or try the free water math drillIdeas the questions test most
- lb/day = mg/L × MGD × 8.34.
- Cylinder volume = 0.785 × D² × depth; 1 ft³ = 7.48 gal.
- Water hp = gpm × head ÷ 3,960.
- 1 MGD = 694 gpm; 1 cfs = 448.8 gpm.
Start the free water math drill · TCEQ Class D Water practice test · California T1 practice test · California T2 practice test · California T3 practice test · California T4 practice test · California D1 practice test
Common questions
Do I get a formula sheet?
California gives drinking water examinees its Equivalents and Formula sheet and an on-screen calculator; WPI provides its Formula/Conversion Table; TCEQ allows a non-programmable calculator.
What is the most used formula?
The pounds formula: pounds per day = dose (mg/L) × flow (MGD) × 8.34.
100 questions across the published subjects, with a score for every area and an explanation for every option.
Or try the free water math drillMore operator topics
- Source Water and Wells
- Coagulation, Sedimentation and Filtration
- Water Disinfection and Chlorination
- Corrosion, Iron, Manganese and Fluoride
- Water Lab and Sampling
- Water Mains, Valves and Hydrants
- Distribution Hydraulics and Storage
- Cross-Connection and Backflow
- Drinking Water Regulations
- Pumps, Motors and Equipment
- Operator Safety
- Management, Records and Customer Service
Outlines used for these questions: Expected Range of Knowledge, Drinking Water Treatment Exam (rev. 4/2020, PDF) · Expected Range of Knowledge, Drinking Water Distribution Exam (rev. 4/2020, PDF) · TCEQ: Need-to-Know Criteria for public water system operators · TCEQ: What applicants for wastewater licenses need to know · WPI: 2025 Need-to-Know Criteria.
Game Assessment Prep is an independent practice site, not affiliated with or endorsed by Water Professionals International (WPI, formerly ABC), the California State Water Resources Control Board or the Texas Commission on Environmental Quality. Every question is original; none is taken from a certification exam, an official study guide or another prep provider.