Drawdown test

Plumbing · Private Water Sources · printed page 260 (PDF page 261)

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Book index entries

Well – Draw Down Test Well – Foot Valve Private Water Sources Private Water Sources for Plumbing

Text in the illustration

the greater amount of drawdown, the lower the capacity of the well
if the water supply is strong, the water level in the well will not drop significantly over the course of the drawdown test
water level at start of test
water level at end of test
pump
ground surface
water table
draw down
water
a recovery test measures how quickly the water level in the well returns to normal after the drawdown test is finished
a recovery rate of 3 gallons per minute is considered acceptable in many areas
cross section

Generated explanation

The cross section depicts a well undergoing a drawdown test, with a surface pump lifting water through a pipe and discharging it onto the ground. A foot valve is shown at the submerged lower end of the pipe inside the well casing. The initial water table and the lowered water level during pumping define the drawdown, with a cone-shaped depression in the surrounding groundwater surface. Annotations explain that greater drawdown indicates lower well capacity and that a strong supply produces relatively little water-level drop. A boxed note describes recovery testing after pumping stops and states that a recovery rate of 3 gallons per minute is considered acceptable in many areas.

Components

well well casing surface pump suction pipe foot valve discharge hose

Materials

soil groundwater