(a) No waterworks corporation shall discontinue the supply of water for nonpayment of bills rendered for service or failure to post a required deposit until either:

1. (1) at least 15 days after written notice has been served personally upon the proper person or persons as hereinafter defined;
2. (2) at least 18 days after mailing written notice in postpaid wrapper to the address of such proper person or persons; or
3. (3) at least 15 days after the proper person or persons has either signed for or refused a registered letter containing written notice, mailed to the address of such proper person or persons.

(b) As used in this Part:

1. (1) The term proper person means:

   1. (i) either the owner of the premises where service is rendered, or in lieu thereof, the person, firm or corporation to whom or which the last preceding bill has been rendered and from whom or which the waterworks corporation has received payment therefor; and
   2. (ii) the superintendent or other person in charge of the building or premises where service is rendered, if it can be readily ascertained that there is such superintendent or other person in charge.
2. (2) The term address of such proper person or persons as that term relates to the persons indicated in subparagraph (1)(i) of this subdivision means the address where service is rendered, except that if the proper person has specified to the company in writing an alternate address for billing purposes, such term shall refer to such alternate address.