A typical Reduced Pressure Zone Backflow Preventer for high-hazard protection
Homes and businesses use substances and liquids that could be a major threat to the health and wellbeing of our customers and visitors. For that reason, backflow prevention is assessed and identified according to the risk to the health of consumers.
In Christchurch City Council's district, the backflow risk arising from the activities on a premises is assessed and it is mandatory that an appropriate backflow prevention device is installed at the point of water supply.
All commercial and industrial properties are to have a minimum of medium-hazard protection at the boundary to protect the main water supply. The installation of this device is a condition of supply and is the responsibility of the property owner.
For homeowners, the Council provides low-level protection at the point of connection to the public water supply. It does not protect water from hazards that can occur within the home.
Sometimes the level of protection provided at the water connection may not be enough, especially if activities such as spa baths, swimming pools or dialysis machines exist within the premises. Protection within the premise must be carried out to comply with clause G12 of the New Zealand Building Code.
| Hazard level | Definitions | Premises type | Protection required | What you can do |
| High | Potential to cause loss of life |
Commercial / Industrial premises (e.g. hairdressers, mortuaries, chemical manufacturing, dentists, drycleaners, medical facilities) |
Reduced Pressure Zone Device or Registered Air-Gap |
Contact a plumber experienced in backflow prevention for advice and arrange an assessment and installation. A building consent is required before installation can occur. |
| Medium | Potential to cause illness |
Residential / Commercial / Industrial premises (minimum protection level for commercial / industrial premises) (e.g. swimming/spa pools, in-ground irrigation controllers, dialysis machine, food and beverage manufacturing) |
Testable Dual Check Device |
Contact a plumber experienced in backflow prevention for advice and arrange for an assessment and installation. A building consent is required before installation can occur. |
| Low | Would cause a nuisance (by colour, odour or taste), but would not injure or endanger health |
Residential / Commercial / Industrial premises (e.g. fast-food drinks machines) |
Testable Dual Check Device installed in the meter at the property boundary |
The Council installs dual check devices at water supply connections to domestic premises. If you have areas within your premises that could cause risk to your drinking water, contact the Council or a plumber experienced in backflow prevention for advice. |
Note: Water will not be provided until the backflow prevention device is installed and a commissioning test has been carried out. The device must be certified by a suitably qualified person and a certificate must be sent to Christchurch City Council for code compliance.