Most of the internal piping and appurtenances in the Centre Block date to the reconstruction of the early 1920s. The external domestic cold water supply is unique in that it actually forms part of the internal system with entry to Centre Block from the East and West Blocks. It is therefore possible for water to flow out of Centre Block at either end of the building. There are no water meters located on the internal watermain system in the building, and past water usage rates have been assessed from meters recording water consumption for all of Parliament Hill. City water pressure being insufficient, most of the building is supplied from a pumped storage system.
Water is pumped to storage reservoirs located in the sixth floor towers.
Domestic cold and hot water supply systems are duplicated for the Commons and the Senate sides. Special water use areas are the cafeteria and restaurant. During the summer, offices located on the south side of Centre Block are supplied with air conditioning units which operate with once-through cooling water. The water audit was to identify the uses of water for the entire facility as well as to recommend options for reducing the overall requirement for water and to carry out a cost-benefit analysis for each option. For future monitoring purposes, the most accurate water consumption data will be generated by the installation of permanent flowmeters.