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Wells, pumps and power: California D1 water distribution operator math

Drawdown, specific capacity, horsepower, efficiency, pumping cost.

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. Before pumping, the water level in a well is 98 ft below ground. After pumping for several hours it stabilizes at 237 ft below ground. What is the drawdown?

  1. A) 237 ft
  2. B) 168 ft
  3. C) 335 ft
  4. D) 139 ft
Show the answer and worked solution

Answer: D) 139 ft

1. Drawdown = pumping water level − static water level (the denominator of [Sheet p.1, Pumping: "Specific Capacity (GPM/Ft) = Well Yield (GPM) / Drawdown (Ft)"]). 2. = 237 − 98 = 139 ft. 3. Answer: 139 ft.

Source: CA Exam Conversion Sheet (Revised 4/30/2026), p.1, Pumping: "Specific Capacity (GPM/Ft) = Well Yield (GPM) / Drawdown (Ft)"

Example 2. Before pumping, the water level in a well is 145 ft below ground. After pumping for several hours it stabilizes at 268 ft below ground. What is the drawdown?

  1. A) 61.5 ft
  2. B) 123 ft
  3. C) 207 ft
  4. D) 413 ft
Show the answer and worked solution

Answer: B) 123 ft

1. Drawdown = pumping water level − static water level (the denominator of [Sheet p.1, Pumping: "Specific Capacity (GPM/Ft) = Well Yield (GPM) / Drawdown (Ft)"]). 2. = 268 − 145 = 123 ft. 3. Answer: 123 ft.

Source: CA Exam Conversion Sheet (Revised 4/30/2026), p.1, Pumping: "Specific Capacity (GPM/Ft) = Well Yield (GPM) / Drawdown (Ft)"

Example 3. The static water level in a well is 103 ft below ground. While the pump runs, the drawdown is 88 ft. How far below ground is the pumping water level?

  1. A) 239 ft
  2. B) 382 ft
  3. C) 279 ft
  4. D) 191 ft
Show the answer and worked solution

Answer: D) 191 ft

1. Drawdown = pumping water level − static water level (the denominator of [Sheet p.1, Pumping: "Specific Capacity (GPM/Ft) = Well Yield (GPM) / Drawdown (Ft)"]), so pumping water level = static water level + drawdown. 2. = 103 + 88 = 191 ft below ground. 3. Answer: 191 ft.

Source: CA Exam Conversion Sheet (Revised 4/30/2026), p.1, Pumping: "Specific Capacity (GPM/Ft) = Well Yield (GPM) / Drawdown (Ft)"

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