1. (1) A utility may only require the payment of a security deposit from:

   1. (i) a seasonal, short-term or temporary customer;
   2. (ii) a delinquent customer, as long as at least 20 calendar days before its request for a deposit, the utility provides the customer with written notice that the failure to make a specified payment before a specified date may result in a request for a deposit and states how the deposit would be calculated; or
   3. (iii) a customer whose service was terminated for nonpayment during the preceding six months.

2. (2) A utility may not require a deposit from:

   1. (i) a customer or applicant who is known to the utility as a recipient of public assistance, supplemental security income benefits or additional State payments; or
   2. (ii) a customer or applicant who is known to the utility as an elderly, blind or disabled person, unless that customer's service was terminated for nonpayment within the preceding six months.

3. (3) If a deposit is authorized by this section, the utility must offer a customer, except for a seasonal, short-term or temporary customer, the opportunity to pay the deposit in installments, considering the customer's financial circumstances in a manner consistent with section 14.10(a)(3) of this Part.

   (b) Deposit calculation.

4. (1) The amount of a deposit must not be more than the cost of twice the customer's average monthly usage, except in the case of customers whose usage varies widely, where the deposit must not be more than the cost of twice the average monthly usage for the peak season.

5. (2) The amount of the deposit must be based on service used during the previous 12-month period, as shown by any relevant billing history, and any relevant information concerning expected use.

   (c) Deposit review.

6. (1) A utility must, at least annually, review the billing history of every customer who has a deposit with the utility, to assure that a deposit may still be required under paragraph (a)(1) of this section and that the amount of the deposit is not more than the amount allowed in subdivision (b) of this section.

   1. (i) If review shows that the deposit held falls short of the amount that the utility may lawfully require by 25 percent or more, the utility may require the payment of an additional deposit amount from the customer.
   2. (ii) If a review shows that the deposit held exceeds the amount that the utility may lawfully require by 25 percent or more, the utility must return the excess deposit to the customer under subdivision (e) of this section.

7. (2) If a request of a customer for a downward revision of the deposit is substantiated by the customer's billing history, a utility must return any portion of the deposit that is more than the amount the utility may lawfully require, under subdivision (e) of this section.

   (d) Interest.

8. (1) Every deposit earns interest at a rate set annually by the commission based on the current economic conditions and current charges paid for money borrowed by such utility, taking into account the expenses incurred by such utility in obtaining, handling, returning or crediting the sum deposited.

9. (2) The interest must be paid to the customer when the deposit is returned, in accordance with paragraph (e)(1) of this section. If the deposit has been held for 12 consecutive months or more, the interest must be credited to the customer no later than the first bill rendered after the next succeeding first day of October and at the end of each succeeding 12-month period.

   (e) Deposit return.

10. (1) A utility must return a deposit or portion of a deposit plus the applicable interest in accordance with paragraph (2) of this subdivision, as soon as reasonably possible, but no more than 30 calendar days after:

    1. (i) the date of the first bill for service rendered after a 12-month period during which time the customer was not delinquent, provided there is no other basis for the utility to request a deposit under paragraph (a)(1) of this section;
    2. (ii) the day an account is closed; or
    3. (iii) a review in accordance with subdivision (c) of this section shows that deposit reduction is warranted.
11. (2) A deposit or portion of a deposit plus the applicable interest that is subject to return under paragraph (1) of this subdivision may be credited to the customer's account in the amount of any outstanding charges, and if any balance remains after the utility has credited the customer's account, a refund check must be issued to the customer.

(a) Deposit requirements.