Water operator math practice, solved step by step

Water math topics

Every practice problem

Work it on paper, then watch it solved one small step at a time.

• Water & wastewaterHow much pressure does 92 feet of water make?Try it, then watch
• Water & wastewaterHow many gallons are in a 20 by 10 by 8 foot tank?Try it, then watch
• WaterHow many gallons are in a 30 foot round tank?Try it, then watch
• Water & wastewaterHow many pounds of chlorine for 2 MGD at 3 mg/L?Try it, then watch
• Water & wastewaterHow do you turn 350 GPM into gallons per day?Try it, then watch
• Water & wastewaterWhat is the area of a 40 by 12 foot clarifier?Try it, then watch
• Water & wastewaterWhat is the flow if 6,000 gallons fill in 30 minutes?Try it, then watch
• Water & wastewaterHow many GPM is 1.44 MGD?Try it, then watch
• Water & wastewaterHow much does 500 gallons of water weigh?Try it, then watch
• Water & wastewaterHow many gallons are in 2,000 cubic feet?Try it, then watch
• Water & wastewaterWhat is the detention time in minutes for 5,000 gallons at 250 GPM?Try it, then watch
• Water & wastewaterHow many feet of head is 50 psi?Try it, then watch
• Water & wastewaterWhat percent of capacity is 400 GPM out of 500?Try it, then watch
• WaterHow many gallons are in a 12 foot round tank, 10 feet deep?Try it, then watch
• Water & wastewaterWhat is the area of a 20 foot round clarifier?Try it, then watch
• Water & wastewaterWhat is the area of a 30 by 15 foot basin?Try it, then watch
• Water & wastewaterHow many pounds of chlorine for 0.5 MGD at 2 mg/L?Try it, then watch
• Water & wastewaterHow much pressure is at the bottom of a 40 foot tank?Try it, then watch
• Water & wastewaterHow do you turn 720,000 GPD into MGD?Try it, then watch
• WaterHow many gallons are in 1,000 feet of 6 inch main?Try it, then watch
• WaterHow many gallons are in 800 feet of 12 inch main?Try it, then watch
• Water & wastewaterWhat is the area of a 25 foot round tank?Try it, then watch
• Water & wastewaterWhat is the area of a 50 by 20 foot basin?Try it, then watch
• WaterHow many pounds of alum for 3 MGD at 12 mg/L?Try it, then watch
• Water & wastewaterHow many GPD is 1,000 GPM?Try it, then watch
• Water & wastewaterWhat is the flow if 12,000 gallons fill in 40 minutes?Try it, then watch
• Water & wastewaterWhat is the detention time for 60,000 gallons at 500 GPM?Try it, then watch
• Water & wastewaterHow much pressure does 150 feet of water make?Try it, then watch
• WaterHow many pounds of chlorine to disinfect a 12,000 gallon main?Try it, then watch
• WaterHow many gallons are in 500 feet of 24 inch main?Try it, then watch
• WaterHow many gallons are in 2,000 feet of 8 inch main?Try it, then watch
• WaterWhat percent of the water is lost if 500,000 is pumped and 450,000 delivered?Try it, then watch

Keep practicing

Common questions

What math is on the Texas Class D water operator exam?

Unit conversions, area and volume, chemical dosage, and flow. It is closed-book, but you are given a formula and conversion sheet, so the skill is knowing when to use each formula, not memorizing numbers.

Are these real exam questions?

No. Every problem is original teaching material written to practice the same math the exam uses. Nothing here predicts your official score.

Is the water math practice free?

Yes. Every worked problem is free, with the full step-by-step walkthrough and a plain-words explanation.

What are the key water constants to remember?

7.48 gallons per cubic foot, 8.34 pounds per gallon, 0.785 for a circle, and 0.433 psi per foot of water. Each shows up again and again.