A Well Casing is a tube-shaped structure placed in the well to maintain the well opening from the target groundwater to the surface. Along with grout, the casing keeps dirt and excess water out of the well.

The casing keeps soil and rock fragments from collapsing into the well shaft, and provides protection for the wiring and water piping connected to the submersible pump near the bottom of the well. State codes often require a minimum of 18 feet of casing in unconsolidated soil (i.e., not solid rock).

Casing pipe is most often used to protect underground utility lines including water mains, electrical high-voltage lines, natural gas lines, telephone lines, and fiber-optic communication lines. This steel casing protects lines from human activity such as drilling or digging as well as from natural elements.

A cracked well casing is a recipe for disaster. If the cover on top of your well casing gets damaged, insects and small animals could crawl inside. If they die and decompose, harmful bacteria may get into your water supply.

Wells get drilled as far down as 1,000 feet into the rock to access the water. A pipe casing gets installed into the hole, and a concrete or clay sealant surrounds it to protect against contaminants. Water travels through this casing via a well pump. The well system gets capped off above ground.

Water well casings can be relined. When a well casing has eroded enough to allow sand and silt to be introduced to the pump, it's time to act.

Drilling a well costs approximately $5,325 to $9,180 for an average depth of 150 feet. Most homeowners spend roughly $3,750 to $15,300, or $25 to $65 per foot for well installation. Digging a shallow well costs roughly $1,800 to $3,000.

Well Deepening: Reentering an existing well and drilling to a deeper reservoir. Well deepening is re-drilling into an already existing well in order to find a deeper more productive reservoir. Sometimes a previously unproductive well can be deepened in order to reach a location with higher flow and temperature.

Increasing the well depth and the length of well casing will result in a longer flow path of water from recharge at the surface to pumping from the well. The longer the length of time water is in the subsurface, the more opportunity there is for bacteria to die off or be trapped by soil and rock.

Here is a good place to start:

https://www.epa.gov/privatewells/learn-about-private-water-wells

Steel Casing

(1) All steel casing installed shall be in new or like new condition, being free of pits or breaks, and shall meet or exceed the minimum American Society for Testing Materials (ASTM A-53A or B) specifications for steel pipe, for the sizes as set out in Table 210-2.

(2) All steel casing having a diameter larger than 20 inches shall have a wall thickness of at least 0.375 inch.

(3) Steel casing installed in a well greater than a nominal diameter of ten inches, having a wall thickness of 0.250 inch and meeting or exceeding ASTM A-53 A or B specifications must not exceed the following depth limitations (Diameter — Maximum Depth, respectively):

(a) 12 inches — 500 feet;

(b) 14 — 16 inches — 250 feet;

(c) 18 — 20 inches — 100 feet.

(4) Steel casings of other ASTM specifications shall not be used without written permission of the Director. A written request to use casing of other specifications shall be submitted to the Director. This request shall include a description of the casing specifications and the reason for its use.

On the Oregon Administrative Rules Database Website:

https://secure.sos.state.or.us/oard/displayDivisionRules.action?selectedDivision=3184