CWD CWD Well Maintenance & Rehabilitation 2

Question 1

Acid treatment of a water well is most effective for which type of fouling?

Accepted Answer

Calcium carbonate and mineral scale deposits

Answer

Acid treatment (typically hydrochloric or muriatic acid) is most effective at dissolving calcium carbonate and mineral scale deposits that block well screens and the surrounding formation.

Question 2

A step-drawdown test is used primarily to:

Accepted Answer

Evaluate well efficiency and identify non-linear head losses

Answer

A step-drawdown test pumps a well at sequentially increasing rates to separate aquifer losses from well losses, determining well efficiency and identifying turbulent (non-linear) head losses.

Question 3

What is the minimum waiting period after shock chlorination before a well can be returned to domestic service according to standard US practice?

Accepted Answer

At least 24 hours, plus a clear bacteriological test

Answer

Standard practice requires waiting at least 24 hours for the chlorine to dissipate and then passing a clear bacteriological test (absent for total coliform and E. coli) before returning the well to service.

Question 4

Which indicator best signals that a submersible pump is wearing out rather than the well declining?

Accepted Answer

Pump amp draw increases while yield decreases

Answer

Increasing amp draw combined with decreasing yield indicates pump impeller wear, as a worn pump draws more current to overcome internal bypass while producing less water.

Question 5

Polyphosphate sequestering agents added to well water are used to:

Accepted Answer

Prevent iron and manganese from staining fixtures

Answer

Polyphosphate sequestering agents chemically bind iron and manganese ions, keeping them in solution and preventing oxidation that causes staining on fixtures and laundry.

(CWD) Certified Well Driller Practice Test

(CWD) Certified Well Driller Practice Test

CWD CWD Well Maintenance & Rehabilitation 2