Table 1. Groundwater facts for Maryland and the District of Columbia

[Withdrawal data rounded to two significant figures and may not add to totals because of independent rounding. Mgal/d = million gallons per day; gal/d = gallons per day. Source: Maryland- Herring, 1983; District of Columbia— Solley, Chase, and Mann, 1983]

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               Population served by Groundwater, 1980
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                                                       MD     D.C.

Number (thousands)  - - - - - - - - - - - - - - - - 1,279      0
Percentage of total population  - - - - - - - - - -    30      0
From public water-supply systems:
  Number (thousands)  - - - - - - - - - - - - - - -  1540      0
  Percentage of total population  - - - - - - - - -    13      0
From rural self-supplied systems:
  Number (thousands)- - - - - - - - - - - - - - - -   739      0
  Percentage of total population  - - - - - - - - -   170      0
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                     Freshwater withdrawals, 1980
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Surface water and Groundwater, total (Mgal/d)- - - 1,400      340
Groundwater only (Mgal/d)  - - - - - - - - - - - -   175      0.8
  Percentage of total - - - - - - - - - - - - - - -    13      0.2
  Percentage of total excluding withdrawals for
    thermoelectric power  - - - - - - - - - - - - -    17      0.4
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                           Category of use
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Public-supply withdrawals:
  Groundwater (Mgal/d) - - - - - - - - - - - - - -    65      0
  Percentage of total Groundwater  - - - - - - - -    37      0
  Percentage of total public supply - - - - - - - -     9      0
  Per capita (gal/d)  - - - - - - - - - - - - - - -   120      0
Rural-supply withdrawals:
  Domestic:
    Groundwater (Mgal/d) - - - - - - - - - - - - -    56      0
    Percentage of total Groundwater  - - - - - - -    32      0
    Percentage of total rural domestic  - - - - - -   100      0
    Per capita (gal/d)  - - - - - - - - - - - - - -    75      0
  Livestock:
    Groundwater (Mgal/d) - - - - - - - - - - - - -     7      0
    Percentage of total Groundwater  - - - - - - -     4      0
    Percentage of total livestock - - - - - - - - -    54      0
  Industrial self-supplied withdrawals:
    Groundwater (Mgal/d) - - - - - - - - - - - - -    34      0.8
    Percentage of total Groundwater  - - - - - - -    19    100
    Percentage of total industrial self-supplied:
      Including withdrawals for thermoelectric power    6      0.6
      Excluding withdrawals for thermoelectric power   18     57
  Irrigation withdrawals:
    Groundwater (Mgal/d) - - - - - - - - - - - - -    13      0
    Percentage of total Groundwater  - - - - - - -     8      0
    Percentage of total irrigation  - - - - - - - -    54      0
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¹Estimated from data in Maryland Department of Natural Resources and Maryland Department of Health and Mental Hygiene, 1983b.