Maryland Code, Environment § 14-207

For the privilege of using geological strata beneath the surface of the earth in Prince George's County or underground storage of gas in volumes greater than the minimum volume specified, a gas storage company shall pay the county an annual underground storage use fee. The fee applies annually to all gas in storage, except the specified minimum volume, on the last day of each calendar year. It is computed at the following annual rates on the commodity charge paid for the gas by the gas storage company, as evidenced by the tariff under which the gas was purchased: