Well Drilling (C-57) · Lesson 6 of 6

Destroying an Abandoned Well: Fill Plan and Volume Check

"Destroying an Abandoned Well: Fill Plan and Volume Check" is lesson 6 of 6 in the Well Drilling (C-57) Learning Hub. It opens with "When a Well Must Be Destroyed" and works through 5 short steps, then a worked example you can check yourself against.

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Steps in this lesson

  1. When a Well Must Be Destroyed
  2. Investigate and Clean Out First
  3. What Goes Where
  4. Placing the Fill and Verifying
  5. Urban Lots and Temporary Covers

The worked example in the course applies this lesson to a realistic job in 7 steps.

What you'll be able to do

  • Explain the main idea of "Destroying an Abandoned Well: Fill Plan and Volume Check" in plain language you can use on the exam.
  • Apply this step with confidence: "What Goes Where".
  • Apply this step with confidence: "Placing the Fill and Verifying".
  • Apply this step with confidence: "Urban Lots and Temporary Covers".
  • Test yourself on the worked example and the quick-check quiz inside the classroom.
Destroying a Well: Fill Plan and Volumenative soilSEALCLEAN FILL8-in boreGround surfaceUpper20 ftRemaining280 ftbottom up, no free fallUrban lot: dig 5 ft, cap with sealWORKED EXAMPLE: 8-IN BORE, 300 FTArea = π/4 x (8/12)² = 0.3491 sq ftWhole bore: 0.3491 x 300 = 104.7 cu ft104.7 x 7.48 = 783 galUpper 20 ft seal: 0.3491 x 20 = 6.98 cu ft= about 52 gal of sealing materialRemaining 280 ft: 97.7 cu ft of clean fill= about 731 gal; no organic matterVerify: volume placed at least 104.7 cu ftIf only 98 cu ft goes in, the hole is not fullSeal upper 20 ft, fill the rest from the bottom up: 104.7 cu ft totalPlaced volume must equal or exceed the empty hole (Sec. 23.C.7)Source: DWR Well Standards (Bulletin 74-90/74-81), Part III, Sec. 21-23 (23.B.1, 23.C.7, 23.E)CC
The diagram for this lesson, exactly as it appears in the Learning Hub.

The first steps of this lesson

Step 1: When a Well Must Be Destroyed

Under Part III of the DWR Well Standards (Bulletin 74-81 as supplemented by Bulletin 74-90), a well is considered abandoned or permanently inactive if it has not been used for one year, unless the owner demonstrates intention to use it again (Section 21). An inactive well kept for future use needs a lockable cover that cannot be removed without tools, a watertight cover where openings are below ground or if the well is inactive more than five consecutive years, a visible marker, and a clear surrounding area. All abandoned wells and exploration or test holes shall be destroyed (Section 22). The 2026 License Law Reference Book adds that the Well Completion Report (DWR 188) for destruction work is due to DWR within 60 days after the work is complete.

Step 2: Investigate and Clean Out First

Before destruction, investigate the well's condition, details of construction, and any obstructions that will interfere with filling and sealing; downhole television may be used (Section 23.A). Clean out debris, oil from oil-lubricated pumps, and other pollutants. Notify the enforcing agency as soon as possible if pollutants are known or suspected, because work may proceed only with its approval. Where sealing material must also fill the annular space or nearby voids, perforate or puncture the casing, and in some wells remove part of the casing as the well is filled.

The remaining 3 steps, the worked example and the quiz are in the course. This is a preview. The full lesson, with the step-by-step explanations, a worked example and a quick-check quiz, is inside the classroom.

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