Backflow devices on the Central Coast: registration and yearly testing

General information, not legal or technical advice. Central Coast Council’s backflow prevention page holds its current requirements, forms and policy.

What backflow is

Council defines backflow as water drawn back into its distribution mains after it has already gone into a property’s plumbing. Its page gives two ways that can happen: a sudden fall in pressure in Council’s main after a break, or a property owner using a pump to raise the water pressure on site.

Backflow can contaminate the community’s drinking water, Council says, where a property has faulty internal plumbing, a cross-connection with wastewater pipes, or water siphoned back from hoses left in buckets, tanks or pools. A cross-connection, in Council’s terms, is any link between drinking water and a water source that is not safe to drink, such as recycled water, wastewater or stored water.

A backflow prevention device stops water running backwards into Council’s supply. It lets water travel one way only, from the main into the property, and if the flow reverses it shuts or diverts the flow so contaminated water cannot reach the supply. Council lists the kinds of device: mechanical valves that allow one-way flow, air gaps that physically separate water sources, and specialised assemblies for higher-risk properties.

Which properties need one

The trigger is a hazard rating. A device is required where a plumber has identified the property as a medium to high hazard of backflow contaminating the drinking water system. Council gives examples of property types that could fall into that group:

• commercial or industrial premises
• medical or chemical facilities
• properties whose irrigation system is connected to the water supply
• sites that have fire services
• properties where chemicals, fertilisers or recycled water are used.

The rating itself is not a judgement an owner makes. Council says you must engage an accredited backflow plumber, meaning a licensed plumber with backflow accreditation, to assess the site, and the rating must be done again when the activities on the site change. If a property has more than one connection to Council’s main, more than one containment device will be needed.

The exception is the ordinary house. A device is not required for a 20 mm or 25 mm water service connection that supplies drinking water to a single, low-hazard residential dwelling.

The owner’s six duties

Once a property is identified as needing backflow prevention, Council puts the responsibility on the owner or occupier: the device has to be installed, maintained and managed to Council’s requirements. Its page breaks that into six duties. Council says a qualified plumber carries out the installation, testing and any repairs.

1. Have the hazard rated. By an accredited backflow plumber, and again when the site’s activities change.
2. Have the right device installed. A qualified plumber does the installation, testing and any repairs; the owner’s part is making sure the plumber fits and tests the correct containment device on the water connection to the property.
3. Register it with Council. Containment devices have to be recorded on Council’s register, and the first application carries fees and charges.
4. Have it tested every year. An accredited backflow plumber tests high and medium hazard devices when they go in and every year from then on.
5. Make sure the results reach Council. After installation and after each yearly test, as soon as practicable once the work is done.
6. Keep it working. A fault is repaired, or the device replaced, so the water supply stays protected.

Getting a device onto the register

Council’s application and test-result forms are marked for containment devices only. A Backflow Prevention Device Application, with its fee, is needed in four cases:

After the application is lodged, Council sends the property owner or occupier an invoice. Once it is paid, Council processes the application and issues a Backflow Prevention Device Certification letter to the owner or occupier. This guide prints no fee amount: Council’s Schedule of Fees and Charges sets the fees and is reviewed every year.

The yearly report

Every testable device is tested once a year, and the results go to Council each year. As read on 9 October 2026, Council’s page says no fees apply to lodging the annual inspection and maintenance reports.

Not sure whether a property has a testable device? Council says testable devices are put in by an accredited backflow plumber and need regular testing, and that a property with one should have received a test report or certificate after installation or a yearly test. They are often larger assemblies with valves and fittings in view, not small inline valves, and Council suggests asking a licensed plumber where you are unsure.

Council keeps a record of containment devices and may send yearly reminder notices to help, but its page is clear that the owner or occupier stays responsible for getting devices tested and results lodged on time.

What Council does with the register

Council keeps a register of every testable backflow device installation and monitors compliance with the backflow requirements. Its page lists its part: recording and managing registrations for containment devices, receiving and reviewing test reports, monitoring compliance with the relevant standards and requirements, and auditing installations where needed.

If a device or its installation falls short, Council can serve a notice on the owner or occupier to repair, maintain, test or replace it, and not following the notice can lead to further compliance action. Council has also adopted a Backflow Prevention Policy, listed on its page as the 2025 policy, which explains how Council guards its supply, and the health of the people who drink from it, against contaminated water returning into its pipes.