1248 LAWS OF MARYLAND. [CH. 732

levied against any agricultural property until such prop-
erty is connected with said water pipe or sanitary sewer,
and provided, further, that when connected, the length of
agricultural property to be assessed shall be limited to 150
feet. The Commissioners shall change the classification
of properties from time to time as said properties change
in the uses to which they are put. The Commissioners
shall be empowered and directed to make a charge upon
every building and place having a connection with the
sewerage system under their control, said charge to be an
annual sewerage service charge. All assessments and
charges, except connection charges shall be uniform for
each class of property throughout the District, shall be sub-
ject to change annually and shall be collected by the treas-
urer of Baltimore County, as hereinafter set forth, except-
ing the water service rates, which shall be collected a&
already specified in Section 332. For those water supply
systems not falling under the provisions of Sections 331
and 332 but constructed and operated by the Commission-
ers, water service rates, shall be established by the Com-
missioners. All front foot assessments shall run for an
equal term of years; provided, however, that any property
owner may, at his option within one year from the time
said front foot assessment or benefit charge is levied,
extinguish the same by the payment in cash, in one sum,
of the proportion of the estimated cost of the project of
which the construction abutting upon his property is a
part, represented by the number of front feet with which
he is assessed, with interest at the rate of six per cent per
annum from the date of said levy, less any, annual pay-
ment that may have been made thereon. The Commission-
ers, however, in estimating said cost for the purposes of
extinguishment, may add thereto a reasonable margin to
protect themselves against possible changes in the cost of
construction and the loss of interest. All sums received
under such plan of extinguishment shall be preserved
intact by the treasurer of Baltimore County, less the pay-
ment of the proportion of interest and sinking fund prop-
erly chargeable to the amount so received, and used for
further construction. The said assessments and charges
shall be and constitute a lien upon the property charge-
able with the same until paid. Said lien whether as to
assessments and charges heretofore accrued or hereafter
accruing, shall be and is hereby declared always to have
been superior to any and all other liens against the prop-
erty chargeable therewith, whether such other liens were
created prior to or after the passage of Chapter 539 of the
Acts of 1924, known as the Metropolitan District Act.