Working safely with greywater – For plumbers

Tips for Plumbers when setting up a Greywater Diversion System:

• DO ensure that the greywater diversion system has a valve to allow untreated greywater to be diverted back to the sewer when it is too wet to go onto the garden.
• DO ensure there is no cross-connection of greywater with the drinking water supply.
• DO install a diversion device that has a WaterMark license.
• DON’T use greywater diversion devices if the property is connected to a municipal effluent reuse system and the sewerage service provider doesn't allow diversion of wastewater from the effluent reuse scheme.
• DON’T discharge untreated greywater near agricultural drainage pipes as the greywater could flow into the stormwater drainage system.
• DON’T discharge untreated greywater in an environmentally sensitive area.
• DON’T use spray irrigation of untreated greywater as the human health risks are unacceptable.
• DON’T use water from the kitchen, handbasins or toilets for greywater.

When installing a greywater treatment system:

• DO install a greywater treatment system that has been accredited by local/state authorities;
• DO undertake a water audit before installing a greywater treatment system to calculate the amount of greywater that can be generated and used on-site;
• DO mark and label all pipes and use signs to indicate treated greywater use;
• DO ensure the treated greywater irrigation systems complies with state guidelines and plumbing codes; and
• DO use treated greywater for irrigation (including surface irrigation if appropriate), toilet flushing and washing machines only.
• DON’T install any component of an irrigation system within one metre of site boundary and buildings and other hard surfaces and swimming pools.
• DON’T use water from toilets for greywater and avoid water from the kitchen (fats and oil can clog up some treatment systems)