Glossary Category: Water System Terms
Water System Terms is about:
Key terms related to your well’s water production, delivery, and performance. Learn what gallons per minute (GPM), static water level, drawdown, well yield, and aquifer recharge rate mean – and why these measurements matter for sizing your pump system and ensuring a reliable water supply.
An aquifer is a subsurface geological formation that contains sufficient saturated permeable material to yield usable quantities of water to wells. Aquifers are divided into two main types: unconfined aquifers, where the water table is at the top of the saturated zone and is recharged directly by precipitation and surface water; and confined aquifers, which…
Aquifer recharge rate describes how quickly an aquifer regains water lost to pumping or seasonal drawdown through natural infiltration from the surface. For the Spokane Valley–Rathdrum Prairie Aquifer, recharge occurs primarily through precipitation on the Rathdrum Prairie, river and stream infiltration, and seasonal snowmelt from surrounding mountains. The SVRP Aquifer’s high permeability allows for relatively…
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…
Gallons per minute (GPM) is the standard metric used in the well drilling industry to measure a well’s flow rate — the volume of water the well produces per unit of time under pumping conditions. A residential well in Idaho typically needs to produce a minimum of 1 to 3 GPM to support basic household…
A pressure tank (also called a captive air tank or bladder tank) is installed between the submersible pump and the household plumbing system. Inside the tank, a rubber bladder separates a pre-charged air chamber from the water storage chamber. As the pump runs, water fills the tank, compressing the air bladder. When a faucet opens,…
A pump system is the above-well and in-well assembly that draws water from the aquifer to the surface and maintains the household or commercial water supply. A standard residential pump system includes: a submersible pump (installed inside the well casing at depth), drop pipe (connecting the pump to the surface), electrical wiring and controls, a…
Static water level (SWL) is the depth from the surface to the top of the water column in a well under non-pumping (static) conditions. It is measured after the well has rested long enough for the water level to stabilize — typically several hours after any pumping has stopped. The static water level is recorded…
Water testing involves collecting a sample from a well and submitting it to a certified laboratory for analysis. A standard basic test for residential wells includes coliform bacteria, E. coli, nitrates, and pH. A comprehensive test adds hardness, iron, manganese, arsenic, lead, turbidity, and other site-relevant parameters. In Idaho, water testing documentation is required by…
A water tote trailer carries a large portable water storage tank on a wheeled trailer that can be delivered to a property and connected to an exterior fill point or temporary holding tank. Trident Drilling uses water tote trailers as part of its emergency water delivery service to provide potable water to households and properties…
Well yield is the long-term productive capacity of a well expressed in gallons per minute (GPM). It is distinct from instantaneous flow rate because yield accounts for the well’s ability to sustain production over time without excessive drawdown. A well might briefly produce 10 GPM but sustain only 5 GPM over a four-hour pump test…