Maryland Department of Natural Resources

Anne Arundel County Observation-Well Network

Project Details

map of Maryland showing study area of Anne Arundel County

The Anne Arundel County water-level network is one of three county observation-well networks maintained by MGS and funded through county cooperative agreements. Other counties include Charles and Queen Anne’s counties.

Location of network observation wells

The primary objective of these networks is to monitor the effects of water-supply withdrawals on groundwater levels at both a local (well field) and regional scale. More specifically the water-level data are used to help assess (1) long-term sustainability of the water supply; (2) well interference (drawdown at each well in a multiple-well system added to drawdowns at the other wells); (3) potential for increased development of the aquifers; (4) potential for salt-water intrusion, where applicable; and (5) the role of ground-water extraction in land subsidence.

The Anne Arundel County observation-well network, initiated in 1986, is currently funded through a cooperative agreement between Maryland Geological Survey and Anne Arundel County Department of Public Works. The network consists of 42 wells located mainly in the central and northern part of the County. Aquifers monitored include the Patuxent (7 wells), Lower Patapsco (19 wells), Upper Patapsco (9 wells), Magothy (6 wells), and Aquia (1 well). Frequency of measurement is 6 times a year, semiannual (spring and fall), or continuous.



Current Water-Level Trends


Aquia aquifer


Water levels were measured in one well in this aquifer. The most recent water level at the Deale Athletic Field (AA Fe 92) was 34.81 ft below sea level. Over the past year, the water level increased by 0.46 ft. Overall trends since 2005 are relatively flat due to the reduction of regional withdrawals from the Aquia aquifer in St. Mary’s County as pumpage was shifted to the deeper Upper Patapsco aquifer to avoid elevated arsenic concentrations in the Aquia aquifer.

Magothy aquifer


Water levels were measured in six wells in this aquifer. Current levels range from 0.71 ft above sea level at Route 50 and Howard Grove Road (AA Dd 42) to 25.18 ft below sea level at the Traffic Engineering Building, Broad Neck (AA Cf 99). Overall trends since 2015 have continued to be flat in response to withdrawals, with the exception of AA Cf 99 which shows a response to local pumping conditions.

Upper Patapsco aquifer


Water levels were measured in eight wells in this aquifer. Current levels range from 69.76 ft above sea level at Aviation Blvd., Glen Burnie (AA Ad 108) to 35.14 ft below sea level at the Broad Creek Water-Treatment Plant (AA De 95). Recent pumpage in Broad Creek ranged from 0 gallons per day (Dec 2025 and May 2026) to 1.32 million gallons per day (Aug 2025) (tab. 5). Figures 15 and 16 show plots of water levels and pumpage in the Upper Patapsco aquifer. Within the past five years, water levels in the Upper Patapsco aquifer exhibit a relatively flat trend while Aviation Blvd (AA Ad 108) has a generally decreasing trend.

Lower Patapsco aquifer


Water levels were measured in 19 wells in this aquifer. Current levels range from 73.87 ft above sea level at Queenstown Park, near Glen Burnie (AA Bd 160) to 72.63 ft below sea level at the Arnold Water-Treatment Plant (remote site) (AA Cf 167). Recent pumpage in Crofton ranged from 5.98 million gallons per day (Mar 2026) to 8.75 million gallons per day (Jan 2026) (tab. 2). In Arnold, recent pumpage ranged from 2.63 million gallons per day (Apr 2026) to 5.36 million gallons per day (Aug 2025) (tab. 4). Figures 6, 7, 12 and 13 show plots of water levels and pumpage within the Lower Patapsco aquifer. Water levels in this aquifer fluctuated in response to water use, especially at the Crofton Meadows Water-Treatment Plant (AA Cc 115) where water levels fluctuated 31.21 ft over the past year. Despite fluctuations in response to pumpage, overall water level trends are generally flat or decreasing in all wells except at the Broad Creek Water-Treatment Plant (AA De 206).

Patuxent aquifer


Water levels were measured in seven wells in this aquifer. Current levels range from 19.12 ft above sea level at the Patuxent Wildlife Refuge Center (AA Cb 1) to 136.20 ft below sea level at the Arnold Water-Treatment Plant (remote site) (AA Cf 166). Recent pumpage in Crofton ranged from 3.09 million gallons per day (Dec 2025) to 6.49 million gallons per day (Jun 2026) (tab. 1). Recent pumpage in Arnold ranged from 2.58 million gallons per day (Jan 2026) to 4.08 million gallons per day (Aug 2025) (tab. 3). Figures 3, 4, 9 and 10 show plots of water levels and pumpage within the Patuxent aquifer. Over the past year the water level in all of the wells, except for Aviation Blvd., Glen Burnie (AA Ad 90) and the Crofton Meadows Water-Treatment Plant (AA Cc 135), remained declining in response to increased withdrawals. Aviation Blvd. (AA Ad 90) and Crofton Meadows (AA Cc 135), while decreasing over the entire period of data collection, show a generally flat trend within the past five years. Water levels in this aquifer fluctuated in response to water use, especially at Crofton Meadows (AA Cc 135) and Arnold (AA Cf 166) where levels fluctuated as much as 62.29 ft and 37.77 ft, respectively, over the past year.