Backflow

The cost of a backflow test depends on the number of devices on your property, the site layout and where the devices are located. Optiplumb charges $250 + GST to test the first device and $200 + GST for each additional device. If a device fails and needs repair or replacement, we’ll explain the cost before carrying out the work.

Backflow is when water flows the wrong way through a pipe and is drawn back into the drinking water supply. It can happen when water pressure drops, for example during a burst main or when a fire hose is in use nearby. A backflow prevention device is a valve that stops contaminated water from pools, irrigation systems, chemicals or industrial processes entering the public water supply or your own drinking water.

Councils and water suppliers require backflow prevention devices on properties where there is a risk of contaminating the public water supply. If your property has a testable device, the council keeps a record of it and will contact you when a test is due or overdue. Optiplumb's IQP technicians can test your device, carry out any repairs, and supply the test results to the council so your property stays compliant.

Testable backflow prevention devices must be tested at least once a year by a qualified backflow tester. Devices should also be tested when first installed and after any repair or relocation. Regular testing confirms the internal valves and seals are working, as these can wear or fail over time without any visible signs.

Backflow prevention is usually required for commercial, industrial and rural properties, and for homes with a higher contamination risk. Common examples include swimming pools and spas, irrigation systems, fire sprinkler systems, commercial kitchens, medical and dental clinics, car washes, factories, farms using chemical dosing, and rainwater tanks connected to the mains supply. Most standard homes are covered by a low-risk device at the water meter, which does not need annual testing.

The three main types are dual check valves, double check valves and reduced pressure zone (RPZ) devices. Dual check valves are fitted at many residential water meters for low-risk properties and are not testable. Double check valves are used for medium-risk sites and must be tested annually. RPZ devices provide the highest level of protection for high-risk sites such as hospitals, laboratories and chemical plants, and must also be tested annually. The right device depends on the hazard level at your property.

A backflow survey, also called a hazard assessment, is an inspection of your property's water system to identify where contamination could enter the supply and how serious the risk is. The survey confirms whether backflow prevention is needed, which device type is required and where it should be installed. Optiplumb carries out backflow surveys for new builds, commercial fit-outs, change of use and council requests.

An IQP (Independently Qualified Person) is a person registered with the local council to inspect, test and maintain specified systems in commercial buildings, including backflow prevention devices. IQPs provide the inspection reports building owners need for their annual Building Warrant of Fitness (BWOF). Optiplumb's founder Duncan Leask is a registered Backflow Prevention IQP, along with two other IQP technicians.

If a backflow device fails, it is no longer protecting the water supply and must be repaired or replaced before it can pass. Common causes include worn seals, damaged valve springs and debris caught inside the device. Because Optiplumb's IQP technicians are also certified plumbers, we can often repair the device on the spot, retest it and complete the paperwork in one visit, which reduces downtime for your business.

Yes, for commercial buildings where backflow prevention is listed on the building's compliance schedule. Backflow prevention is one of the specified systems that must be inspected annually by an IQP. The IQP's report is used by the building owner to issue the annual BWOF to the council. Optiplumb can manage backflow testing and reporting for building owners, property managers and facilities managers across the Waikato.