In its area of operation, HSY provides for the distribution and sewage drainage of domestic water in accordance with the needs of community development. Within the water supply service area, the property must join the HSY water supply network. The data contains each municipality's area of action, which is valid for legal force in accordance with the municipality's decision. Areas may be from different years due to different schedules in the approval process. Preliminary areas of expansion are non-binding.
In addition to HSY, water supply services in the territory of HSY member municipalities are provided by water cooperatives and other water management facilities. The operating areas of these other water supply service providers are set out in the file “Other service areas of water supply”. The data also contains information on the area of operation of domestic water alone (includes only domestic water, not drainage).