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Unit conversions and pressure: California T2 water treatment operator math

Flow, volume, pressure/head and concentration conversions; meters; SCADA signals.

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 hardness test reports 15 grains per gallon (gpg). What is the hardness in mg/L?

  1. A) 0.877 mg/L
  2. B) 125 mg/L
  3. C) 514 mg/L
  4. D) 257 mg/L
Show the answer and worked solution

Answer: D) 257 mg/L

1. 1 gpg = 17.1 mg/L [Sheet p.1, Units and Conversion Factors, row 18: "1 gpg = 17.1 mg/L"]. 2. Hardness = 15 × 17.1 = 256.5 mg/L. 3. Answer: 257 mg/L (rounded to 3 significant figures).

Source: CA Exam Conversion Sheet (Revised 4/30/2026), p.1, Units and Conversion Factors, row 18: "1 gpg = 17.1 mg/L"

Example 2. A pressure gauge on a distribution main reads 155 psi. How many feet of head does this represent?

  1. A) 67.1 ft
  2. B) 179 ft
  3. C) 358 ft
  4. D) 119 ft
Show the answer and worked solution

Answer: C) 358 ft

1. 1 PSI = 2.31 Ft [Sheet p.1, Units and Conversion Factors, row 31: "1 PSI = 2.31 Ft"]. 2. Head = 155 psi × 2.31 ft/psi = 358.05 ft. 3. Answer: 358 ft (rounded to 3 significant figures).

Source: CA Exam Conversion Sheet (Revised 4/30/2026), p.1, Units and Conversion Factors, row 31: "1 PSI = 2.31 Ft"

Example 3. A pressure gauge is mounted 5 ft above the floor of a storage tank and reads 13 psi. How deep is the water in the tank, measured from the floor?

  1. A) 70.0 ft
  2. B) 35.0 ft
  3. C) 30.0 ft
  4. D) 25.0 ft
Show the answer and worked solution

Answer: B) 35.0 ft

1. 1 PSI = 2.31 Ft [Sheet p.1, Units and Conversion Factors, row 31: "1 PSI = 2.31 Ft"]: water above the gauge = 13 × 2.31 = 30.03 ft. 2. Add the gauge height: 30.03 + 5 = 35.03 ft. 3. Answer: 35.0 ft (rounded to 3 significant figures).

Source: CA Exam Conversion Sheet (Revised 4/30/2026), p.1, Units and Conversion Factors, row 31: "1 PSI = 2.31 Ft"

Want it on paper? Free printable T2 water treatment math worksheet with answer key.

Practice all 300 unit conversions and pressure problems for CA T2 Math

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