Guides

• How WaterTableCheck Calculates a County's Water Table Trend — The exact USGS dataset, qualifying bar, and OLS trend model behind every county's groundwater figure, named and sourced.
• What a Declining Water Table Means for a Residential Well Pump — Why a deeper water table shortens a pump's working life, and what to check before it fails.
• The US Counties Where the Water Table Is Moving Fastest — The fastest-declining and fastest-rising counties in WaterTableCheck's dataset, ranked by the same per-well trend as every county page, not a regional guess.
• Why Some Counties Show No Data, and What a Negative Depth Means — What it means when a WaterTableCheck county page has no qualifying well, and why a handful of wells report water above the surface instead of a depth.