(1)In section 99 of the WIA (financial conditions of compliance with sewer requisition)—
(a)in subsection (2), for paragraph (a) there is substituted—
“(a)bind the person or persons mentioned in that subsection to pay to the undertaker either (at the election of such person or persons)—
(i)in respect of each of the twelve years following the provision of the sewer, an amount not exceeding the relevant deficit (if any) for that year on that sewer; or
(ii)following provision of the sewer, a single amount not exceeding the discounted aggregate deficit on that sewer; and”,
(b)in subsection (6), for the words from “shall be referred” to the end there is substituted “may be referred to the Authority for determination under section 30A above by either party to the dispute.”,
(c)for subsection (7) there is substituted—
“(7)In this section “relevant deficit” and “discounted aggregate deficit” have the meanings given by sections 100 and 100A below, respectively.”
(2)In section 100 of the WIA (calculation of “relevant deficit” for the purposes of section 99), in subsection (8), in paragraph (b), for “that has already been provided” there is substituted “in respect of which the conditions referred to in section 99(1) above have already been satisfied.”.
(3)After section 100 of the WIA there is inserted—
(1)For the purposes of section 99 above the discounted aggregate deficit on a public sewer is the amount equal to the sum of the estimated relevant deficits for each of the twelve years following the provision of the sewer, in each case discounted in accordance with subsection (6) below.
(2)The estimated relevant deficit for any year is the amount (if any) by which the estimated drainage charges payable for the use during that year of that sewer would be exceeded by the annual borrowing costs of a loan of the amount required for the provision of that sewer.
(3)Subsections (2) to (6), (8) and (9) of section 100 above (which relate to the annual borrowing costs of a loan of the amount required for the provision of a public sewer) shall apply for the purposes of this section as they apply for the purposes of that section.
(4)Any reference in this section to the estimated drainage charges payable for the use during any year of any sewer is a reference to so much of the aggregate of any charges expected to be payable to the sewerage undertaker for the provision of services in the course of that year as would represent charges—
(a)imposed by the undertaker in relation to such of the premises with which the sewer is expected to be connected as are premises where there are buildings; and
(b)reasonably attributable to the use of that sewer for the drainage for domestic sewerage purposes of those premises or to the disposal of effluent drained for any such purposes from those premises.
(5)For the purposes of subsection (4) above, a thing is expected to be the case if, at the time the relevant calculation is made, it is reasonably likely to occur.
(6)The estimated relevant deficit for a year mentioned in subsection (1) above shall be discounted in order to determine its net present value by applying such factor, and in accordance with such other provision, as may be determined by the Authority.
(7)A determination made by the Authority for the purposes of subsection (6) above—
(a)may be made in relation to the provision of a particular public sewer or in relation to the provision of public sewers generally; and
(b)may be revoked at any time except in relation to a public sewer in respect of which the conditions referred to in section 99(1) above have already been satisfied.”
(4)The amendments made by subsections (1) to (3) of this section do not apply in respect of public sewer requisitions (as defined in section 100(9) of the WIA) for which notice has been served under section 98(1) of that Act before commencement of the subsection in question.