5SFor the year 1967-68 the cumulo rateable value of the lands and heritages occupied for the purposes of a water undertaking shall be the aggregate of the following—
(a)the average number of units per day of potable water produced by the undertaking and supplied for use within the limits of supply of the local water authority carrying on the undertaking in the year 1965-66, multiplied by the norm;
(b)one half of the average number of units per day of potable water supplied by them in bulk for distribution or use outwith the limits of supply of the local water authority carrying on the undertaking in the year 1965-66, multiplied by the norm;
(c)one half of the average number of units per day of potable water supplied to them in bulk in the year 1965-66, multiplied by the norm;
(d)the average number of units per day of non-potable water supplied by them in bulk for distribution or use outwith the limits of supply of the local water authority carrying on the undertaking in the year 1965-66, multiplied by such fraction of the norm as may be prescribed by order made by the Secretary of State;
(e)the average number of units per day of non-potable water produced by them and supplied for use within the limits of supply of the local water authority carrying on the undertaking in the year 1965-66, multiplied (subject to paragraph 6 below) by such fraction of the norm as may be prescribed by order made by the Secretary of State; and
(f)the average number of units per day of non-potable water supplied to them in bulk in the year 1965-66 multiplied by such fraction of the norm as may be prescribed by order made by the Secretary of State.