22. (1) Irish Water may, from time to time, and shall when so directed by the Commission, prepare and submit to the Commission a plan (in this Act referred to as a “water charges plan”) for the charging of customers for the provision of water services.

(2) A water charges plan shall apply in respect of such period as the Commission shall direct.

(3) A water charges plan shall specify—

(a) the manner and method by which charges under section 21 shall be calculated, and

(b) the costs likely to be incurred by Irish Water in the performance of its functions under this Act during the period to which the water charges plan relates.

(4) (a) A water charges plan may, where the quantity of water supplied to a premises is measurable by a meter, make provision for charges under section 21 to be calculated by reference to the quantity of water supplied to, and the quantity of waste water discharged from, that premises.

(b) A water charges plan may, where the quantity of water supplied to a premises is not measurable by a meter, make provision for charges under section 21 to be calculated by reference to an assessment by Irish Water of—

(i) the quantity of water supplied to the premises concerned, and

(ii) the quantity of waste water discharged from the premises concerned,

determined in such manner and by the application of such formula as is specified in the plan.

(5) A water charges plan may make provision for charges under section 21 in respect of the provision of a service connection (within the meaning of the Act of 2007) to or in respect of a premises.

(6) A water charges plan may specify—

(a) different methods in relation to different classes of customer as respects the calculation of charges under section 21,

(b) different rates of charge under that section as respects different classes of customer, and

(c) different methods of payment in respect of charges under that section.

(7) Irish Water shall, when preparing a water charges plan take account of the following matters:

(a) the need to ensure that Irish Water performs its functions in a commercially viable manner;

(b) the public utility nature of its functions; and

(c) the need to maintain a balance between the matters referred to in paragraphs (a) and (b).

(8) The Commission may, having regard to the most recent investment plan provided to the Commission under subsection (8) of section 34 F10[, the most recent strategic funding plan most recently furnished by the Minister under section 34A(5)(b) (inserted by section 19 of the Water Services Act 2017)] and the costs likely to be incurred by Irish Water in the performance of its functions during the period to which a water charges plan submitted to the Commission under this section relates—

(a) approve that water charges plan with or without modification, or

(b) refuse to approve that water charges plan.

(9) For the purposes of calculating a charge under section 21, the amount of waste water discharged from a premises is deemed to be equal to the amount of water supplied to that premises, unless Irish Water and the customer agree otherwise.