Persons obligated to pay sanitary sewer service charge.

The owner or occupant of each building, establishment, or other place in the District connected with any District sewer conducting sanitary sewage shall pay the sewer service charge authorized by this subchapter. If the sanitary sewer service charge imposed by this subchapter is based on a water charge any part of which is for a period beginning prior to the imposition of the sanitary sewer service charge and ending thereafter, the sanitary sewer service charge shall be prorated, on a monthly basis, on so much of such water charge as shall have accrued subsequent to August 1, 1954. In computing the charge for sanitary sewer service, if such charge is for a period beginning prior to a change in the established sanitary sewer service charge and ending thereafter, the charge shall be based on the rate in effect at the time the charge is rendered.