(a)      For the purpose of providing funds for the design and construction of trunk sewers and those sewers or portions of sewer lines required to relieve septic tank failures and for which no front foot benefit charges can be collected as determined by the WSSC, sewage pumping stations and sewage disposal facilities including reimbursement to the District of Columbia or other federal authorities for any construction within the District of Columbia after January 1, 1951, the WSSC created by Chapter 122 of the Acts of the General Assembly of Maryland of 1918, may issue bonds of the sanitary district from time to time, in amounts it considers necessary, but the aggregate amount of bonds issued under this section shall be included in and subject to the 7.0 percent limitation under § 4-101(e) of this subtitle. Bonds issued under the authority of this section shall be serial bonds with the principal of any given issue payable annually, commencing not more than 3 years from the date of the bonds. The bonds may be either registered or coupon bonds, or registerable as to principal with interest represented by coupons, and issued in a denomination or denominations as shall be determined by the WSSC, with interest at such rate or rates per annum as provided in § 4-104 of this subtitle payable semiannually and with a maturity date not exceeding 40 years from the date of issue. All bonds of the WSSC issued pursuant to the authority of this section are exempt from taxation by the State of Maryland and by the counties and municipalities in the State.

      (b)      They shall be issued under the hand and seal of the WSSC and shall be guaranteed as to payment of principal and interest by Montgomery and Prince George's counties, which guarantee shall be endorsed on each of such bonds in the following language: "The payment of interest when due and the principal at maturity is guaranteed by Montgomery and Prince George's counties, Maryland". The bonds of the sanitary district shall be signed by the chairman and the secretary and the treasurer of the WSSC or, if the WSSC shall so provide, by any 2 of its members, and the official seal of the WSSC shall be impressed upon the bonds; provided, however, that the WSSC may authorize any of such officials to sign the bonds with his facsimile signature; except that each of such bonds shall be manually signed by at least 1 of such officials; and provided, further, that the WSSC may authorize a facsimile of the official seal of the WSSC to be imprinted on the bonds, in which case it shall not be necessary that such official seal be impressed physically upon the bonds. Such guarantee or endorsement by Montgomery and Prince George's counties shall be signed on each of such bonds on behalf of each county by the County Executive of each county or by any officer designated for such purpose by the County Executive, by his facsimile or manual signature as the County Executive shall each respectively determine, within 20 days after the bonds are presented by the WSSC for the signing of such endorsement. In the event of any liability under the above guarantee, such liability for each county shall be in such proportion as the assessable basis of that part of either county within the sanitary district bears to the assessable basis of the whole of such district. Notwithstanding the foregoing provisions of this subsection, the WSSC may, at its option and pursuant to the provisions of § 4-103 of this subtitle, waive the guarantee of such counties above provided for.

      (c)      For the purpose of retiring bonds authorized to be issued by this section, and payment of the interest thereon, there shall be levied against all of the assessable property within the sanitary district, by the County Councils of Montgomery and Prince George's counties, annually so long as the bonds are outstanding and not paid, a tax sufficient to meet the interest on the bonds, and to pay the principal thereof as the principal and interest mature or become due; the tax shall be determined, levied, collected and paid over to the WSSC in the manner provided by § 4-105 of this subtitle, and all of the provisions of § 4-105 of this subtitle shall apply to the bonds issued hereunder.

      (d)      (1)      For the purpose of retiring the bonds authorized to be issued by this section and the payment of the interest thereon and for the purpose of paying for the cost of the maintenance of its sewerage system and its disposal facilities, including the overhead expense and proper depreciation allowance, and payments to the District of Columbia for disposal of sanitary district sewage, the WSSC shall be empowered and directed to make a sewer usage charge, chargeable against all properties connected to the WSSC's sewerage system. Except as provided in paragraphs (2) and (3) of this subsection, the charges shall be based upon the water consumption of the properties connected to the sewerage system.

            (2)      Where the WSSC furnishes sewerage service to a property which is not connected to the WSSC's water system the WSSC shall make a sewer usage charge on an annual, semi-annual, or monthly basis, which will fairly and ratably compensate the WSSC for the use of the sewerage system by such property, and in fixing the charge for properties not connected to the water system the WSSC shall take into consideration the usage made of the sewerage system by such property and the sewer usage charge applicable to like or similar properties connected to the water system.

            (3)      (i)      Except as provided in subparagraph (ii) of this paragraph, in the event that water furnished by the WSSC to any lot or parcel of land shall be used exclusively for any purpose which results in the water not entering the sewerage system of the WSSC, then and in that event the owner, tenant or occupant of such lot or parcel shall not be charged a sewer usage charge for the water so used, provided, however, that the owner, tenant or occupant of such lot or parcel shall pay to the WSSC the cost of installing such a separate metered connection as well as an annual amount equal to the WSSC's annual water service charge for the size of the meter so installed for measuring the water so used and which meter connection upon such payment shall be installed at a location to be determined by it and shall thereafter be maintained and exclusively controlled by the WSSC under such rules and regulations as the WSSC may adopt.

                  (ii)      A commercial, industrial, or multiresidential property may use a separate metered connection as provided in subparagraph (i) of this paragraph, even though a portion of the separately metered water enters the sewerage system of the WSSC, provided that the owner, tenant, or occupant of the property requests to be billed according to a formula determined by the WSSC.

                  (iii)      The formula determined by the WSSC under subparagraph (ii) of this paragraph shall:

                        1.      Credit the owner, tenant, or occupant for separately metered water not entering the sewerage system of the WSSC; and

                        2.      Be consistent with:

                        A.      Manufacturers' engineering standards for the class of equipment utilizing the separately metered water supplied by the WSSC; or

                        B.      Industry standards for the class of operations utilizing the separately metered water supplied by the WSSC.

                  (iv)      The sewer usage charges for properties under subparagraph (i) of this paragraph shall be based on the total amount of water used as determined under § 6-104 of this article, less the amount of separately metered water.

                  (v)      The sewer usage charges for properties under subparagraph (ii) of this paragraph shall be based on the sum of:

                        1.      The total amount of water used as determined under § 6-104 of this article, less the amount of separately metered water; and

                        2.      The amount of separately metered water as adjusted by the formula described in subparagraph (iii) of this paragraph.

            (4)      Wherever the property of any federal, State or other agency is exempt from front foot benefit charges and ad valorem taxes imposed under the provisions of Chapter 122 of the Acts of the General Assembly of Maryland of 1918, and amendments thereto, and the property is connected to the WSSC's sewerage system, the WSSC shall make a sewer usage charge against the property so connected, with full authority to change the same from time to time, which charge shall take into consideration the general tax, and front foot benefit charge levied within the sanitary district in addition to the regular sewer usage charge provided herein.

            (5)      The sum of sewer usage charges collected annually for the payment of principal and interest due on outstanding bonds shall be deducted from the amount which the WSSC has determined to be necessary to be raised by direct taxation upon certification to the County Councils of said counties.

            (6)      (i)      Bills for the amount of the sewer usage charges shall be sent monthly, quarterly or semi-annually, as the WSSC may determine to each property connected to the sewerage system, and shall be thereupon payable at the office of the WSSC.

                  (ii)      If any bill shall remain unpaid after 30 days from date of sending, the WSSC shall after written notice, to be left upon the premises or mailed to the last known address of the owner, turn off the water from the property in question and it shall not be turned on again until the bill shall have been paid.

                  (iii)      If any bills shall remain unpaid for 60 days after being sent out by the WSSC it shall be collectible against the owner of the property served, in the same manner as other debts are collectible in the respective counties.

            (7)      The provisions of this section shall not be construed as authority to repudiate any existing contracts between the WSSC and any municipality located within the sanitary district without the consent of the municipality.