Assessments of Oklahoma's groundwater occur through both a baseline monitoring network and a long-term (trend) monitoring network within each of the state's major aquifers, providing information on individual aquifer characteristics as well as a more general assessment. Through quality analyses, the natural geochemistry of the aquifers is assessed to identify concerns.

Water samples are taken from existing groundwater wells and analyzed for parameters such as nutrients, dissolved metals, alkalinity, hardness, dissolved oxygen, pH, and total dissolved solids. A sub-set of wells from the baseline monitoring network will be used for trend monitoring, evaluated multiple times per year.

Multiple assessments of water level and chemistry will facilitate recognition of seasonal changes, changes due to climate variability, and/or changes due to usage over time. The differences in these changes as well as aquifer response will be identified in all of the State's major aquifers. To further facilitate this effort, a select number of wells have been equipped with water level data loggers to monitor changes on the scale of weeks, days, or even hours.

OWRB staff collect groundwater samples from select LMFO monitoring wells and submit them to the ODAFF’s laboratory for analysis of potential contamination of groundwater, signaled through high nitrate-nitrogen concentrations, high ammonium-nitrogen concentrations, or sample analyses containing three or more fecal coliform colonies. Quarterly and annual reports of findings are submitted by OWRB staff.