University of Maryland Extension

Well Anatomy

Maryland has established guidelines for the construction of wells. All wells must be constructed by licensed well drillers in accordance with State regulations. The well must pass inspection and the water must be certified as potable (drinkable) by the County Health Department before the well can be used. [Maryland Health Departments numbers and addresses.] The following components of a typical domestic well are illustrated on the accompanying figure.

CASING: A metal or plastic pipe used to line a portion of the bore hole. The minimum length (depth) of the casing is determined by State regulations based on the geology of the area. The casing must extend a minimum of 8 inches above the ground (24 inches in flood zones) to keep storm water runoff out of the well.

GROUT: Material used to provide a watertight seal between the bore hole and the casing to prevent surface water and contaminants from running down the side of the well. Grouting may be portland or quick-setting cement, or bentonite clay. The minimum depth or length of casing that must be grouted is also determined by state regulations.

WELL COVER: A cap that screws or clamps onto the top of the well casing to prevent contaminants from entering the well.

SCREEN: A pipe-like attachment at the bottom of the well. Well screens are usually not required when drilling in bedrock, but they may be necessary if loose sand or fragmented rock is encountered. The screen is sealed on the bottom and has openings along its length that allow water to enter the well, but keeps out sand and sediment.

PUMP: Draws water from the bottom of the well and into the distribution system. Many types and sizes of pumps are available. The two most commonly used are submersible and jet pumps. Submersible pumps are installed in the well and can be removed relatively easily with the pull rope. Jet pumps have the motor located outside the well.

PITLESS ADAPTER: Provides a frostproof and sanitary hookup between the well and the household water distribution system. The pitless adapter must be located below the frost line.

Schematic of a Well

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