Drought and a drying climate
is a reality we're all having to deal with,
so it makes sense to make the most of whatever water we have.
For many of us, the idea of greywater reuse
became topical during the millennium drought,
and with so much of the country facing water shortages once again,
it's a good time to revisit how we can make the most of greywater.
Greywater is household waste water
that doesn't include water from the toilet.
Kitchen sink and dishwasher water should also be avoided,
as it contains food scraps and grease.
The simplest way to reuse greywater is manual bucketing,
which you can do from the shower or the laundry trough
to keep a few plants alive.
Now, it's cheap, but it's also hard work.
A better way to go is direct diversion.
Now, in new homes like ours,
all the plumbing's under the ground,
so you need to design that in at the time of building.
But for older homes or homes that are raised off the ground,
often the plumbing can be accessed.
Now, we've mocked this example up.
This is something that you might see coming out from either the laundry
or the shower and bath recess.
This is a job for a plumber.
They'd cut into this and install one of these.
This is an approved direct-diversion valve.
And the plumber would install that.
And what it means
is you can either have the greywater going straight to sewer
or you can divert it and have it going out to the garden.
From there a piece of flexible hose can be installed
to take the greywater out to the garden.
And then a piece of slotted drainage pipe is connected,
and this is the part that will disperse the greywater in the garden.
Now, this needs to be installed into a shallow trench covered with soil,
and that means the greywater can permeate into the garden
and not pond on the surface.
Now, the length of this slotted ag pipe
and the size of the drainage trench
needs to be sized up in accordance
with local guidelines,
and that's to make sure that it can actually take
the estimated volume of greywater generated
suited to your local soil type.
That's important to make sure that greywater doesn't back up
and also can disperse properly without ponding.
That system will set you back about $100 in materials
plus the time of a plumber.
One of the drawbacks of a trench system, though,
is that it only distributes the greywater
in a pretty limited area.
You're not really making the most of it.
So the next step along is something like this.
This has a surge tank to temporarily hold the greywater
as it's coming from the house.
Also it has a filter.
You can see it. There you go.
And this is to catch any coarse material in the greywater.
And there's also a pump in the bottom of that sump,
and what happens is the greywater comes in,
it goes through the filter, wells up,
the pump picks up there's water in there
and it's pumped out to the garden.
This unit has its own diversion valve inside and an overflow point.
In the event there's a malfunction of the pump,
the greywater will automatically overflow to sewer.
Now, that'll cost you around $1,000
and it's suited to a single stream of greywater,
like shower and bath or laundry.
And you can see by the size of the pipe
it's for those small flows of greywater.
This one - consider it the big brother.
This is a whole-of-house system.
And the principle of operation is very similar.
There's a filter, there's a pump.
And the beauty of these pump systems
is it means you can actually pressurise the water
and send it out to the garden and run it through drip line
to really get a much broader dispersion of that water.
My greywater system is also a whole-of-house type,
with these units costing around $3,000.
They both have self-flushing filters,
which greatly reduces maintenance.
So what plants are suited to greywater?
Well, all sorts.
Have a look at this crepe myrtle - it's absolutely loving it.
Or my bananas - a really thirsty plant
which are happily producing fruit here.
Also the pomegranate's doing well.
Shrubs like the rosemary and the salvias and my grapevines
producing all on greywater.
Now, I've got the greywater drip line
neatly laid out through this garden area
just like you would do with regular drip line,
but, importantly, the colour of the pipe is purple,
and that's the international standard for waste water.
And that pipe is then covered with a thick layer of mulch
to prevent contact and reduce any risk of passing on pathogens.
Now, every time my greywater system comes on,
all of this area and the plants in it get a really good drink.
It's not a good idea to apply greywater to pots
as it will pool at the bottom.
Also avoid using it on vegies,
where there is the potential for contact
between greywater and the part of the plant that you eat.
It's also important to be mindful
of the cleaning and personal-care products you use.
Basically choose ones that are designed for greywater reuse.
And if you do need to use disinfectants
or hair dye or bleaches,
make sure you divert your greywater to sewer.
Now, despite best intentions, all detergents are alkaline,
and over time they'll raise the pH of the soil,
so don't use it on things like
camellias, azaleas, blueberries or other acid-loving plants.
I find even with my citrus
that, after a period, it starts to show up symptoms of chlorosis -
that is the yellowing of the leaves
because the pH of the soil means the plants have a hard time
getting all the trace elements they need.
So I fix this quite simply
with a regular application of liquid trace elements
as a foliar feed,
which I apply about every six weeks
during periods of heavy greywater use,
and I find the plants respond beautifully.
Regularly composting and adding mulch WEBVTT
will maintain good soil health
and will also buffer against an increase of pH.
Switch off your greywater system during rainy periods
to rest the soil and also flush out any accumulated salts.
As you can see, there's a fair bit to greywater reuse
if you want to do it efficiently and responsibly.
But if you're short of water, I reckon it's well worth it.
To find out more about greywater regulations in your area,
you'll find some helpful links on our website.