1. (1) the balance of any bill for service, including levelized bills and any unpaid late payment charge amounts applied to previous bills, which bill is not paid within 20 calendar days of the date payment was due;
2. (2) the amount billed for service used that was previously unbilled because the service was being provided through tampered equipment, and the utility can demonstrate either that the condition began since the customer initiated service or that the customer actually knew or reasonably should have known the original billing was incorrect; and

3. (3) the balance due under a deferred payment agreement offered pursuant to section 13.5(a)(1)(i) of this Part.

   (b) Other charges.

   Except as provided in this section, a utility may not charge any customer a late payment charge, penalty, fee, interest or other charge of any kind for any late payment or deferred payment agreement occasioned by the customer's failure to make timely payment for services. Nothing in this section shall prohibit a utility from imposing a reasonable charge pursuant to its tariff for other lawful purposes, such as for a dishonored check, for reconnection of service, the failure to provide access, or court costs.

(a) Late payment charges.

A utility may impose a continuing late payment charge as provided for in its tariff on: