WaterExamMath
Practice free

Practice › CA T3 Math › Area and volume

Area and volume: California T3 water treatment operator math

Pipe, tank, basin, trench and wall areas and volumes; force on a valve.

Below are 3 worked examples. Each answer is computed with the formulas and constants on the CA Exam Conversion Sheet (revised 4/30/2026), and the solution names the line it uses.

Formulas from the sheet for this topic

Example 1. A rectangular basin is 55 ft long and 56 ft wide, with water 14.5 ft deep. How many gallons does it hold?

  1. A) 23,000 gal
  2. B) 334,000 gal
  3. C) 44,700 gal
  4. D) 372,000 gal
Show the answer and worked solution

Answer: B) 334,000 gal

1. Rectangular Basin (Gal) = L × W × H × 7.48 [Sheet p.1, Area and Volume: "Rectangular Basin (Gal) = Length (Ft) x Width (Ft) x Height (Ft) x 7.48"]. 2. = 55 × 56 × 14.5 × 7.48 = 334,057 gal. 3. Answer: 334,000 gal (rounded to 3 significant figures).

Source: CA Exam Conversion Sheet (Revised 4/30/2026), p.1, Area and Volume: "Rectangular Basin (Gal) = Length (Ft) x Width (Ft) x Height (Ft) x 7.48"

Example 2. A rectangular basin is 95 ft long and 11 ft wide, with water 18 ft deep. How many gallons does it hold?

  1. A) 282,000 gal
  2. B) 157,000 gal
  3. C) 141,000 gal
  4. D) 1,170,000 gal
Show the answer and worked solution

Answer: C) 141,000 gal

1. Rectangular Basin (Gal) = L × W × H × 7.48 [Sheet p.1, Area and Volume: "Rectangular Basin (Gal) = Length (Ft) x Width (Ft) x Height (Ft) x 7.48"]. 2. = 95 × 11 × 18 × 7.48 = 140,699 gal. 3. Answer: 141,000 gal (rounded to 3 significant figures).

Source: CA Exam Conversion Sheet (Revised 4/30/2026), p.1, Area and Volume: "Rectangular Basin (Gal) = Length (Ft) x Width (Ft) x Height (Ft) x 7.48"

Example 3. A cylindrical storage tank is 40 ft in diameter with water 22 ft deep. How many gallons does it hold?

  1. A) 5,170 gal
  2. B) 27,600 gal
  3. C) 207,000 gal
  4. D) 827,000 gal
Show the answer and worked solution

Answer: C) 207,000 gal

1. Cylinder Volume (Gal) = .785 × D² × Height × 7.48 [Sheet p.1, Area and Volume: "Cylinder Volume (Gal) = .785 x D2 x Height or Length (Ft) x 7.48"]. 2. = .785 × 40 × 40 × 22 × 7.48 = 206,687 gal. 3. Answer: 207,000 gal (rounded to 3 significant figures).

Source: CA Exam Conversion Sheet (Revised 4/30/2026), p.1, Area and Volume: "Cylinder Volume (Gal) = .785 x D2 x Height or Length (Ft) x 7.48"

Want it on paper? Free printable T3 water treatment math worksheet with answer key.

Practice all 74 area and volume problems for CA T3 Math

Free account: practice sets drawn from 74 problems on this topic, worked solutions, missed problems come back, and readiness by topic for CA T3 Math. Also works in ChatGPT and Claude.

Practice this topic freeTry 5 problems first

Other CA T3 Math topics

WaterExamMath is independent practice software. It is not affiliated with, endorsed by or connected to the California State Water Resources Control Board. It covers the math portion of the drinking water operator exams only, not the whole exam, and passing is not guaranteed. Problems by WaterExamMath.