Safe Water Reuse First
There is a certain amount of paperwork that comes with the Australian greywater recycling systems guidelines, yet what they are about is simple enough: you are to reuse household wastewater in a manner that is safe and in keeping with state, territory and local council regulations, all while safeguarding public health. While greywater can take some of the load off your potable water supply for garden or indoor purposes, having a bucket and a hose and being sanguine about it is no substitute for a system in compliance.
I am Elowen Fairchild. I have the same approach to a household system as I do to the fine print on a skincare label or hotel Wi-Fi; one reads the details, is sceptical of any vague assurances and makes sure of the contingencies. In this guide I put the requirements for a greywater system in Australia into plain English, from the regulations in each state and treatment options to the kind of errors that tend to befall homeowners.
What You Will Find At Home
By way of definition, greywater is the wastewater you get from the laundry, washing machine, bathroom basins, bath and shower. It is not to be confused with blackwater from the toilet which presents a far greater risk to public health. Water from a kitchen sink or dishwasher is another matter altogether; with its organic loads, grease and food particles it may not be fit for easy diversion and is often treated as such. These distinctions support safe household drain practices.
The quality of the water from a shower or the washing machine will vary according to how long it has been sitting and the products, chemicals and nappies used in the home. For the most part untreated greywater is best put to use right where it is, rather than left in a warm tank for the bacteria to make of it what they will.
Picking Your Sources
A basic diversion can be set up to take water from the laundry or shower to the garden. Then there are more sophisticated greywater treatment systems that will disinfect and filter for a controlled reuse, say for the toilet, provided the approval pathway and system are in order.
In an Australia greywater project the end use, source and degree of treatment should be in harmony. Do not think of a diversion for ornamental plants as being in the same class as a system tied to your internal plumbing. The difference is material when it comes to getting approval and safety.
An Estimate Of Volume
Before you put money down on equipment, do a rough calculation. Say you have four in the house putting out 40 litres of shower water apiece, that is 160 litres a day to start with, not counting the laundry. This is by way of example only; the real figures are a function of your occupancy, the fittings you have and so on.
Doing the maths will save you from the twin pitfalls of a system that cannot handle the demand or one that puts out more greywater than the plants and soil will take. The latter results in odours, sodden ground and neighbours who are none too pleased. One does not want the backyard to be the venue for the local mozzie conference.
State And Council Regulations
You will not find a single national rulebook for greywater. The various demands of the building, health, environmental and local government authorities have a way of overlapping. Councils in particular can be insistent on matters of location, discharge, storage and the like.
Make a call to your local council and the appropriate state health or plumbing authority before you alter any plumbing or buy a diversion device. Be specific in asking if you require a permit, registration, an inspection or the go ahead from the health department.
Following The Proper Channel
Even adjoining councils can have different rules. Sydney Water will have its own guidance for customers in its area, and you will find information on what is permitted from Penrith City or Frankston City Council. See them as a prompt to do your own checking rather than a licence to imitate what the neighbour has done.
Be circumspect with the term “approved system”. A product might be certified for a given purpose but that is not the same as approving its installation at your place. There may be issues with the slope, drainage, groundwater or setbacks on your site.
National Guidelines
For a framework on the risks of recycled water there are the Water Quality Australia and the Australian Guidelines for Water Recycling. They are informative on exposure and risk management but they are not a substitute for what the state or council says.
Regulators or the manufacturer may point to AS 4995-2009 in relation to domestic greywater. As a homeowner you should verify what edition and evidence of compliance is called for with the system you have in mind. Do not be taken in by a sales page making reference to a standard and think the matter of approval is settled.
Put The System To The Task
What matters is not the tank’s colour or make. The critical decision is one of kind: do you have a need for a simple diversion or a treatment system that has been put to proper engineering? Get the category wrong and you will be looking at contamination, costly rework and having an uncomfortable word with the plumber.
Diversion Versus Treatment
| System type | Typical application | What it controls | Usual worry |
|---|---|---|---|
| Manual bucket or the like | For prompt use on garden areas as needed | None; no long-term storage | Inconsistent results, overflow |
| Greywater diversion (laundry, bathroom) | Automatic sewer diversion, filters, plumbing to send water outside | Soil saturation, detergents | |
| Treatment system | Filtration, disinfection, monitoring for non-potable recycled water of a better quality | Neglected servicing, equipment failure | |
| Advanced reuse | Backflow protection and regulatory sign-off for toilet flushing or the like | Cross-connection with potable supply |
A diversion will put water in an approved outdoor spot. There must be a failsafe to put the flow back in the sewer if the household is using the wrong products, the soil is saturated or the system is down. An automatic sewer diversion is a good thing to have since one cannot put a schedule on the weather or what goes on in a house.
With treatment systems the process can vary, from screens and sand filters to biological treatment, settling, cartridge filters or UV. Do not be fooled by the brochure into thinking UV is some sort of miracle; it will not disinfect with a dead lamp. It needs the right clarity of water and up to date maintenance.
Where Approval Is Called For
If greywater is being pumped, stored or treated, or is near where people might come in contact with it, approval is called for. The same holds true if wastewater is to cross onto neighbouring land, be discharged in a manner harmful to the environment or find its way to stormwater and property lines.
There are fewer formalities for a case of temporary reuse but “fewer” does not mean there are none. Make a call to your council to be sure of the threshold before you start putting in a tank or digging trenches; it is cheaper than undoing an installation that is not in compliance.
Questions To Put To The Authority
In describing the situation, give them the daily volume, the source and end use of the water, the soil, the discharge area and how long it is to be stored. Whether it is for an ornamental plant, a toilet or an edible crop should be made clear. A rough sketch of the site will help, showing any slopes, boundaries, drains and the irrigation zone.
Find out who is qualified to put in and certify the work. Where there is a risk of contaminating potable water or pipework has to be altered, a licensed plumber is usually required. Any installer worth his salt will be versed in isolation valves, sewer bypasses and backflow prevention.
Sensible Use Of Untreated Water
For immediate outdoor use under control, untreated greywater is fine, provided there is no likelihood of contact. Sub-surface irrigation is the way to go to avoid odour and evaporation while keeping the water out of sight. Be circumspect with shrubs and trees. One does not want to see it pooling on a path or being sprayed about. And never make a connection to a drinking-water pipe or a tap that could be taken for potable water.
Food And Family Considerations
Produce to be eaten raw, such as root crops and leafy vegetables, are more of an exposure concern than fruit that is harvested above ground and given a good wash. Heed professional opinion and local rules when it comes to edibles.
Fresh discharge is not a place for pets or children. Nor should greywater be used where someone has a medical condition or an open wound. Just because it has been in the shower does not make it innocuous; cleaning agents and laundry can alter the risk.
Soil And Plant Health
The soil has to be able to take the water as fast as it is put there. Sandy ground will let it run off and may not hold moisture or nutrients; clay and compacted earth will become saturated in short order. A slope has a habit of taking water downhill to the neighbour’s paving.
After a rain, have a look at the ground and rotate the discharge point if you can. If there are white deposits, the plants are not doing well or there is a bad smell, something is amiss. A saturated site is not evidence of a system doing its job, more often it means you are putting too much water on it.
Better Cleaning Products
Opt for a low-sodium or low-phosphorus detergent if your appliance and local recommendations allow. While biodegradable products are an option to lessen the environmental footprint, one should not equate “biodegradable” with being right for any plant, soil or treatment system. There is still potential for trouble from fragrances, bleach, solvents, disinfectants, strong stain removers and hair treatments.
Greywater lines are no place for workshop liquids, pool chemicals, pesticides, paint or kitchen grease. Should you have a load of harsh chemicals in the machine, put the water to the sewer. And keep a maintenance log on the greywater system for any product changes, filter cleaning, pump alarms, unusual odours or times the system has been bypassed.
Proper Installation and Maintenance
The point of a sound installation is that it is hard to misuse and simple to get at for inspection. You need pipe identification that is unambiguous, the right filters, overflow control and a way to service it. There should be a dependable bypass to an approved disposal point or the sewer; when the system does not perform on a wet week you do not want to be playing guessing games in the backyard.
- Before making a purchase, see what the council and health authorities require.
- Have a licensed plumber put in hand where necessary and get the certificates or records to show for it.
- Make sure recycled and potable water are kept apart.
- Put in a diversion or sewer bypass that is easy to access.
- Do not size your irrigation to the maximum a marketing brochure will claim but to what the soil can actually take.
- Filters, pumps, valves and outlets should be cleaned and looked over as the manufacturer would have it.
- If there is flooding, heavy rain, an outbreak of illness, a bad smell or an overflow in plain sight, put the system out of commission.
- Non-potable outlets need to be labelled and out of reach of children.
Maintenance is more than an annual formality. After a storm or power failure, or if you have had renovations or switched laundry products, give the system a once-over. Treatment systems call for calibrated sensors, disinfection checks and new filters from time to time. A unit left to its own devices might seem fine from the street but be a public health issue in truth.
Mistakes With Greywater
The assumption that all greywater is created equal is where most go wrong. Water from a quick shower is not the same as from a wash of nappies or very soiled things. It may appear clear yet have its share of microorganisms and chemicals. Then there is the error of putting up with days of untreated water in storage, in warm conditions especially.
Homeowners do not give enough thought to overflow. An outlet becomes blocked and the water has to go somewhere. Lacking a bypass it could end up in a crawl space, a pond by the foundation, the footpath or the stormwater. That is hardly greywater irrigation, just a plumbing conundrum that could have been put to rights.
Reality Check
You might think a greywater system is the end of garden watering. In fact it is a useful supplement at best, subject to the vagaries of rainfall, occupancy, the plants and the soil.
Recycled water is not going to put money back in your pocket straight away. The cost of the plumbing, servicing, approval fees, filters and pumps can be more than any short-term gain. What makes sense is lower demand on potable water and good management.
And as for an online DIY greywater system Australia result being reason to break ground? An internet diagram is no substitute for an assessment of cross-connection risks or local rules. Fixed installations warrant a professional opinion, even if a bucket or two of temporary reuse is a different matter.
Some Questions Homeowners Put To Me
These are the sort of things I would have an answer to before I put down any money or moved a paving slab. Rules are not set in stone, so put in with your state authority and the local council to be sure of the final position prior to installation.
Is a DIY greywater system permissible in Australia?
In some cases. Jurisdiction, location and the system itself will dictate the answer. A fixed setup with pumping and storage is viewed differently than something you do manually and temporarily. One thing is certain: a DIY job must not put drinking water at risk of cross-connection, discharge into stormwater or make for unsafe pooling. Your council can tell you if they need to inspect or have a licensed plumber on site.
What do the Australian Guidelines for Water Recycling say?
They offer a framework for risk management at a national level, covering everything from hazards and monitoring to the reliability of treatment. But they are guidance, not a way around state plumbing law or the need for council sign-off. Read them to know the risks and then abide by the rules for your property.
Shower water is greywater?
It is, as is water from the bath, laundry or bathroom basin. Whether it is fit for reuse is contingent on the cleaning products used, how it is treated and stored and what you intend to do with it. Do not drink it or put it on every food crop without question.
Any drawbacks to these systems?
There are costs for installation and upkeep, the odd odour, clogged filters, salt or nutrient accumulation and the like. They can be obliging about approvals too. Power goes out or it rains hard and they can fail. A sensible plan will mitigate the risks but this is not an appliance you can fit and forget.
Toilet flushing with greywater?
You can if you have a non-potable system in place that has been designed and approved for the purpose, complete with backflow protection and the rest. But do not make a weekend project of hooking up a toilet cistern to untreated greywater. The exposure and plumbing risks are greater with internal reuse than a controlled diversion outside.
A Plan For Reuse
Match the system to your climate, household, soil and the rules of the locality and you will have the safest arrangement. Be judicious with your products and have a bypass in place for when the system or the weather lets you down. Measure the volume you are likely to be dealing with and start with the simplest form of reuse.
I would put it this way: use greywater to cut down on waste, not to add a chore involving pipes to your day. Get the approvals, let a licensed plumber handle the plumbing and keep the recycled water well clear of your drinking supply. Maintain it as you would if someone was to depend on it. That is what safe drain practice is all about.
