(a) Residential Service.
(1) "Residential service" is defined as service to a householder or tenant living in a separate house or a separate apartment in an apartment building.
(2) Should the owner of a multiple apartment building undertake to furnish water to his tenants as a part of their monthly rent, then such service shall be classed as "Commercial."
(3) A close member of a householder's family, living with that householder and using the same water facilities, shall not be classified as an additional service or as "Commercial."
(4) In cases where a householder or tenant devotes some portion of the occupied building to commercial use and uses the remainder as a residence, then the predominant use of water shall constitute the basis for classification as either residential or commercial.
(b) Commercial Service.
(1) "Commercial service" is defined to include service to each separate business enterprise, occupation, or institution occupying for its exclusive use any unit or units of space as an entire building, entire floor, suite of rooms or a single room, and using water for such incidental use as the schedule of rates applicable to the particular installation may permit. "Commercial service" shall apply to all stores, offices, hotels, wholesale houses, garages, display windows, signs, theaters, barber and beauty shops, churches, opera houses, auditoriums, lodge halls, schoolhouses, banks, bakeries, and any other space occupied for commercial purposes. Any rooming house, lodging house, resort, inn or tavern renting more than four rooms to strangers or transients, without any previous agreement for accommodation or as to the duration of stay, shall be classed as a hotel and as such it comes under the "Commercial" classification.
(2) Where a single business enterprise or institution occupies more than one unit of space in the conduct of the same business, each separate unit will be metered separately and considered a separate service unless the customer makes the necessary provisions whereby the different units may be connected to permit the metering of all water used through one meter. The above rule shall not be construed to allow any customer to secure combined meter readings and billings by reason of ownership in the same person, partnership, association, or corporation of different buildings or units of space which are not used and operated by the customer and held out to the public as one single business unit.
(c) Industrial Service. - "Industrial service" is defined as a customer manufacturing or producing a commodity for the use and sale to the general public.
(d) Fire Protection Service. - "Fire protection service" is defined as each customer taking service under a distinct fire protection rate schedule.