Drawdown
Definition
Drawdown measures how much the water level inside a well drops when a pump is operating. As the pump extracts water, the level inside the well casing falls until an equilibrium is reached between the pumping rate and the rate at which water flows from the surrounding formation into the well. A well with a small drawdown produces water almost as fast as it is pumped, indicating a highly productive formation. A well with large drawdown — where the pumping level drops significantly below the static level — indicates lower permeability or a less productive zone. Drawdown data is measured during pump testing and is used to calculate specific capacity, which helps determine appropriate pump settings and long-term sustainability of the well’s water supply.
Frequently Asked Questions
Why Drawdown Matters
How Trident Drilling Company Uses It
Trident Drilling measures and records drawdown data during the pump test conducted at every well completion. This information is documented in the well log and provided to clients. Because Trident refers pump installation to qualified partners, drawdown data is also shared with the pump installer to ensure the pump is set at the correct depth for safe, sustainable operation.