2019 New York Laws
PBS - Public Service
Article 2 - Residential Gas, Electric and Steam Utility Service
41 - Finality of Certain Utility Charges.

§ 41. Finality  of  certain  utility  charges.  1. Notwithstanding any
  other provision of law,  no  utility  corporation  or  municipality  may
  charge  a  residential  customer  for  gas or electric service which was
  rendered more than six months prior to the mailing of the first bill  to
  the  customer  for such service unless the failure of the corporation or
  municipality  to  bill  sooner  was  not  due  to  the  neglect  of  the
  corporation  or  municipality  or was due to the culpable conduct of the
  customer. If the customer remains liable for such service,  the  utility
  shall  permit  payments  to  be  made under an installment payment plan,
  provided, however, that the utility or municipality may  require  prompt
  payment  if  the  non-billing  resulted from the culpable conduct of the
  customer.  Any  such  installment  payment  plan  may  provide   for   a
  downpayment  of  up to one-half of the amounts due from the customer, or
  three months average billing, whichever is less.
2. Notwithstanding any other provision of law, a  utility  corporation
  or  municipality  may  not adjust upward a bill previously rendered to a
  residential customer after the expiration of twelve months from the time
  service to which the adjustment pertains was provided unless (a) failure
  to bill correctly was caused by the customer's culpable conduct  or  was
  not  due  to  the  neglect  of  the  utility  or  municipality; (b) such
  adjustment is necessary to adjust a budget payment plan;  or  (c)  there
  was  a  dispute  between  the  utility  or municipality and the customer
  concerning the  bill  during  the  twelve-month  period.  A  utility  or
  municipality  issuing  an  additional  or  increased  bill  charging for
  services rendered twelve or more months prior to such date  of  issuance
  shall include with it a notice giving the reason for the late billing.
3.  No  public  utility  company or municipality may render a bill for
  previously  unbilled  service,  or  adjust  upward  a  bill   previously
  rendered,  to a residential customer after the expiration of twenty-four
  months from the time service to which the bill  or  adjustment  pertains
  was  provided.  This provision shall not apply when the culpable conduct
  of a customer caused or contributed to the failure  of  the  company  or
  municipality to have rendered a timely or accurate billing.