It has become a trend to replace the traditional single baseline RTK approach by using network RTK services, whilst there is still lack of authoritative guidelines and specifications with this most recent development of GNSS positioning. For this purpose, the Ministry of Transportation of Ontario (MTO), Canada is interested in the performance, as well as specifications and guidelines, for the use of network RTK services in southern and eastern Ontario in control and engineering surveys with three existing network RTK services in that area. This manuscript presents a brief summary of our studies in evaluating the performance of each network RTK service and developing specifications for the use of network RTK in control and engineering surveys. Hundreds of hours of network RTK data were collected from three over lapping network in southern and eastern Ontario. The performance metrics evaluated include: measurement availability, time to first fix, position precision, accuracy, long-term repeatability, solution integrity, and moving average filtering.A subset of results from the data analysis is described, along with the discussion of all of issues and suggestion of potential network RTK field procedures.