Greywater installation and maintenance
Use an experienced greywater installer
An experienced greywater professional should always be used to design and install a greywater system. Contact details for qualified professionals can be found on the GWIG website.
Greywater system maintenance
All greywater reuse systems require regular maintenance to ensure reliable long-term operation. This maintenance however is less than that required for a residential swimming pool and can be broken down into the component parts of a reuse system – pump, filter/s, irrigation system, landscape (plant
and soil health) and diversion to sewer. A partnership between the owner and the installer is the most effective way to maintain a system as the installer can advise on the frequency of inspection and maintenance depending on the design features/technology of the specific unit.
The greywater pump requires occasional inspection to ensure it is operating effectively and there are no blockages, which can cause clogging and eventual pump failure.
The filter at the inlet of the GDD removes a variety of materials that may clog the pump or irrigation system and result in overflow to sewer, wasting greywater.
Depending upon the specific model of GDD installed there may be a coarse primary filter (e.g. sponge, mesh or a screen bag) before the pump to remove hair, lint and gross particles, and a secondary filter (e.g. disc type) after the pump to remove finer particles which could potentially clog the dripline emitters. Instructions on how to clean these filters, and how often, will be described in the operating manual supplied by the manufacturer.
New technologies which incorporate automatic filter back- flushing systems have become available in recent years and reduce the frequency of manual cleaning for the primary filter.
Irrigation system and flushing dripline
Any dripline system must incorporate the ability to flush water through and clean out the inside of the pipes by adding flush valves to the downstream end of pipes. This can be done either individually or via a manifold connecting several together.
Air release or vacuum breaker valves release air from the dripline when water enters the pipe, and allow air to freely re-enter the pipe when the water is shut off, thereby preventing a vacuum from being created which can suck debris back into the drippers.
Both the vacuum breakers and flush valves should be periodically inspected when the system is running to ensure they are operational. They can also be readily opened and visually inspected, removed and cleaned out, or parts replaced, as required. Knowing where these valves are located in an established garden by means of an ‘as-laid’ diagram can help with ongoing maintenance.
The dripline should be periodically inspected for leaks and clogged drippers, with any exposed dripline re-covered with mulch to a depth of 100mm. Signs of damage or faulty dripline include water spraying from breaks in the line, water logging of the ground, excessively green vegetation and or dry/desiccated vegetation.
Soil and plant health inspection
Periodic inspection of plant and soil health is recommended and soil and leaf tissue analysed if there are concerns. There is limited data on any long-term impact resulting from the regular application of greywater to sandy soils. By the end of the summer some plants may show signs that the increased alkalinity from irrigation with greywater is limiting their uptake of essential trace elements, evident by yellowing of leaves and other symptoms related to chlorosis. Using detergents designed for greywater application and switching of systems to ‘rest’ the soil when irrigation isn’t necessary is the best way to minimise negative impacts on soil health.
Diversion to sewer
The ability to divert greywater to the primary sewerage system is mandatory to divert low- quality water away from the garden or to avoid over-watering during winter. A full system flush is recommended at either the start or end of winter. This is achieved by opening the manual flush valves and running higher pressure scheme water through the entire irrigation network until lines run clear.
Scheme water top-up
A scheme water top-up may be required for garden irrigation when the dwelling is unoccupied.