CWD Well Maintenance & Rehabilitation Flashcards

The primary purpose of a pitless adapter in a well installation is to:

Answer: Allow the discharge pipe to exit the casing below the frost line without a pit

A pitless adapter allows the water supply pipe to exit through the well casing below the frost line, eliminating the need for a below-grade pump house pit while maintaining a sanitary seal.

What minimum annular seal depth is required by most US state regulations for a new domestic well?

Answer: 20 feet

Most US state regulations require a minimum grouted annular seal of 20 feet from the surface to prevent contamination from surface water migration down the outside of the casing.

During a pump test, 'recovery data' refers to:

Answer: Water level measurements taken after pumping stops to track aquifer recharge

Recovery data are water level measurements recorded after pumping ceases, tracking how quickly the aquifer refills the well — this data helps determine aquifer transmissivity using the Theis recovery method.

Iron bacteria in a well are best characterized as:

Answer: Non-pathogenic bacteria that oxidize iron and form reddish-brown slime

Iron bacteria (such as Gallionella and Leptothrix) are non-pathogenic organisms that oxidize dissolved iron, producing characteristic reddish-brown gelatinous slime that can foul screens and pipes.

A well driller notices the static water level has permanently dropped 40 feet over 10 years in an area of heavy agricultural irrigation. This most likely indicates:

Answer: Long-term aquifer overdraft from regional pumping exceeding recharge

A permanent multi-decade decline in regional static water levels is the hallmark of aquifer overdraft, where cumulative regional pumping (agriculture, municipal) consistently exceeds natural recharge rates.

Before lowering rehabilitation tools into a well, the driller should always:

Answer: Remove the pump and measure the casing ID and depth to obstructions

Before any rehabilitation work, the driller must pull the pump and measure the casing inside diameter and depth to any obstructions to ensure tools will fit and not become stuck.