Onsite service enterprises (OSEs) are enterprises that develop and maintain systems and facilities that provide services to occupants of a building or a precinct. Examples of onsite services include hot water, energy, lighting, waste and recycling, mobility, food preparation and delivery, childcare, exercise, education and personal care. The full capital and operating costs of providing these services, including installing and maintaining systems, equipment and facilities, are borne by the enterprises and transparent fair costing models are used to determine fees charged for services to ensure there is a reasonable return for the enterprises and that services are affordable. The paper shows how the concept of OSEs can be applied to a housing development near Alexandra, Johannesburg. A critical evaluation of this application in relation to affordability and sustainability is carried out to determine the significance of the approach. The paper concludes that the OSE concept has significant potential and provides detail on how it can be developed and investigated further.