A Sydney Water Tap In application will be required if you're building/developing in Sydney, this requirement is usually outlined in your Council DA, Construction Certificate paperwork or by your Certifier and/or Architect/designer. The Tap In application is completed online, and involves drawing your proposed plans and providing details on the proposed building works. The online system will either approve your proposed plans or refer you to see a Water Servicing Coordinator (WSC) if you're building close or over a Sydney Water asset.