What Is Drawdown in a Well

Drawdown: The drawdown in a well is the difference between the pumping water level and the static (non-pumping) water level. Drawdown begins when the pump is turned on and increases until the well reaches “steady state” sometime later.

How do you calculate water well drawdown?

Subtract the measurements you collect as the pump is running from the static water level. The difference is the drawdown. For example, if the static water level is 1 foot below the top of the casing and the water level after one hour is 3 feet below the top of the casing, the drawdown at one hour of pumping is 2 feet.

What is a good flow rate for a well?

5 gpm (two fixtures running simultaneously at 2.5 gpm) is a good estimate of peak demand, for the typical household. Water wells that reliably yield 5 gpm should be able to meet peak and daily needs for most residences. Wells yielding less than 5 gpm, however, are sometimes the only water source available.