Arkansas Department of Health & Human Services
Division of Health
Center for Local Public Health - Environmental Health Branch - Engineering Section

According to EPA, yes, they are. EPA states:

"We believe that to "sell" should be given broad meaning under the SDWA. Construing the statute this way is consistent with the purpose of the SDWA which is to assure that the water supply systems that serve the public meet minimum national standards for protection of public health to the maximum extent. (House Report No. 93-1185). The House Report further says, in explaining this provision, that Congress intends the primary drinking water regulations to apply to housing developments, motels, restaurants, trailer parks, and other business serving the public if the business in question maintains its own well or water supply and sells water.

A distributor of water for human consumption "sells" water within the meaning of the Act if it charges consumers for the water as a separate item or bills separately for the water it provides. (House Report No. 93-1185). Conversely, if the entity includes the charges for water in the rental fee, then it is not selling water within the context of the Act. It is irrelevant whether water is sold for a profit or not, or whether the distributor is a public or private entity. Thus, it is appropriate to interpret to "sell" to include submetering.

If an apartment building or similar residential community that submeters wants to avoid PWS classification, it would either need to remove the complex's master meter and allow the local water utility to bill the residents directly, or include water usage as part of the monthly rent or fees."