Water Audit – Target 155

It’s easy to be lulled into a false sense of security, thinking we have an endless supply of freshwater. I mean, we turn on the tap and out it comes! It even falls from the sky! Surely it’s renewable and there’s plenty to go around right? The earth’s surface is around 70% water however, only around 2.5% of that is freshwater. Much of that fresh water is locked away in glaciers, snow and underground stores that are challenging to access. So really we currently have access to around 1.5% of that total water. 

To further exacerbate the problem, the planet is becoming more populous. Cue more water needed for drinking, food and sanitation. And we’re also on a very dangerous slippery slope of consumerism addiction (one pair of jeans requires 10,000 L of water to manufacture). According to the Word Bank, in most regions of the world, over 70 percent of freshwater is used for agriculture, of the 1.5% of available freshwater, 23% is used to to hydrate livestock which leaves us with just over 1% for all our other needs. By 2050, feeding a planet of 9 billion people will require an estimated 50 percent increase in agricultural production and a 15 percent increase in water withdrawals. Then add climate change in the form of more intense droughts, heatwaves, floods and polar ice melts to the mix and the freshwater reserves and looking pretty grim.

Those most at risk of running out of water are the poor and marginalised. It’s estimated that by 2050, 50% of the world’s population will be under water stress, with very little access to the diminishing fresh water reserves. Will water become a commodity like oil? Will it be that only the rich can afford the price of freshwater, leaving those on or near the poverty line parched and sick from drinking unsanitised water? You might think that this problem won’t affect you, but aside from Antarctica, Australia is the driest continent in the world, and according to the Australian Government, approximately 35% of our landmass is considered desert.

This map shows the projected change in terrestrial water storage by the end of the 21st century, compared to the 1975-2005 average, under a mid-range scenario for global warming. A continuum of yellow to orange to dark red reflects increasing severity of loss of stored water; teal to blue to dark blue reflects increasing gains in stored water. Yadu Pokhrel, et al, Nature Climate Change, 2021, CC BY-ND

Findings from a study published in The Conversation show the declines in total water storage, including groundwater, may lead to more water shortages during dry seasons when trees need stored water the most. This will exacerbate future droughts and weaken the resilience of forests. This means not only will we run out of water, but forests and the wildlife that rely on them will too run out of freshwater.

What About Desalination?

Desalination is the process of removing salt from sea water. According to an article published by the ABC, desalination is one of humankinds earliest water treatment inventions and dates back as far as ancient Greece. Desalination works by reverse osmosis, a water purification process that removes unwanted particles and membranes from drinking water. The remaining salty water is then returned to the ocean. And not to worry about all that extra salty water going back into the sea, a study by The University of Sydney has found it has very little ecological impact on the our oceans. Great!

Most states in Australia have working desalination plants, with Victoria’s plant having the capacity to deliver up to 150 billion litres of water per year, or about one third of what we need. However, unfortunately desalination is not the panacea to all our water woes. Not only does it not cover all our water needs, the process of reverse osmosis is very energy intensive. This in turn contributes to more greenhouse gases entering the atmosphere and exacerbating the effects of climate change. On a good note, both the plants in NSW and Victoria are offset through renewable energy but is that enough?     

Or Recycled Water?

Here in Australia we use treated sewage (which includes wastewater from homes, the commercial sector and industry as well as stormwater runoff) for industry (farming, outdoor sporting venues etc.). But what about for drinking and personal use? This is already happening in some parts of the world that are water deficit, like Namibia in Southern Africa, who have been drinking treated waste water since the 1960’s.

Is this a real possibility for worldwide adoption? Can we get over the taboo of drinking poo water? What about the cost? It’s estimated the cost of turning Namibia’s sewage into potable water is approximately twice the price of conventional water supply. Although, according to an article published by The Guardian, desalination plants cost roughly twice as much as recycling water. In the same article Prof Stuart Khan, of the University of New South Wales, says “recycled water for drinking should be the “next frontier” as communities try to build their resilience to drought and climate change”. So in short, recycling water should be our next choice over desalination.

And thus, the two biggest barriers to using recycled water are:

  • Our own attitudes towards using recycled water (many of us vote against using it when push comes to shove) and,
  • The overall cost

Target 155

In an age where we are using far more water than previous generations and with many more people to support, it’s so important to be mindful of our own personal usage (although industry needs a swift kick up the arse too). When the desalination plants are switched on, it’s you and I that pay the cost of running them through our water bills. To encourage individuals to limit water consumption, the Victorian Government has launched Target 155 calling on households to use 155 litres of water per person, per day. It also turns out, here in Victoria, we have permanent water saving rules in place to ease the pressure on the dwindling supplies.

According to our last quarterly water bill we used on average 265 litres per day, or 66.25 per person. The same time last year, when we were only three people, we used on average 227 litres a day, or 75.7 per person. This is obviously well below the 155 target but I’m taking into account our rain water tank, which reduces the amount significantly. According to Smart Water Mark, “outdoor water use accounts for 25-50% of the average home’s water”.

A dripping tap can waste up to 12,000 litres a year

Smart Water Mark

Audit Summary

“About 40% of all water used in the home is in the bathroom and much of that is wasted… 1/4 of that is flushed down the toilet.”

Smart Water Mark

We’re fortunate enough to have a 22,500L water tank that services our garden and drinking water. This stays full pretty much all winter but can get to below half during summer. We don’t water the lawn, ever, and only water the garden from mid spring to around the end of autumn – depending on rainfall patterns. Ideally it would be great if this was hooked up to the toilet and laundry and may be worth looking into.

Where We Do Well

  • Turning off the tap whist brushing teeth
  • We have installed water saving shower heads in both bathrooms (7L/min)
  • Have dual flush toilets installed
  • Follow the “if it’s yellow let it mellow, if it’s brown flush it down” rule for the toilet
  • Only filling the bath to a third and only every other day for the kids (bathing is overrated!)
  • Washing vegetables in a sink of water rather than a running tap
  • I use some of the leftover liquids from cooking/drinking to water indoor plants
  • We only run the dishwasher on a full load – interestingly a study by the University of Bonn in Germany found a full dishwasher uses about 13 litres of water to clean 144 items, whilst washing the same load by hand uses about 100 litres of water on average!
  • We try to only put on full loads of laundry (with the exception of cloth nappy rinsing)
  • When we purchased our washing machine I chose a water efficient front loader with a good water rating
  • I’m lucky to wash the car once  year and when we do I drive it onto the grass so the runoff is doing something useful

Room For Improvement

  • We do not collect shower water or bucket the bath water onto the garden – we used to but I found with the water tank, which doesn’t seem to drop below half, the effort to do so outweighs the amount of water collected. I’d probably do it if we didn’t have ‘such a large tank
  • Again we don’t catch any grey water from either the kitchen or the laundry for the same reasons above
  • We don’t time our showers and at a guess I’d say they run for more than 4 minutes. Although, full disclosure, we don’t shower everyday – before you judge, Harvard Medical School states “daily showers do not improve your health, could cause skin problems or other health issues — and, importantly, they waste a lot of water.” They suggest showering several times per week is plenty for most people (most being those that don’t get overly sweaty or dirty – i.e. me)
  • We do A LOT of laundry given we have two small humans in the house that struggle to get food in their mouths. We also use cloth nappies which require a prewash and a long wash. A lifecycle assessment study completed by the UK Environment Authority in 2008 found that cloth nappies do in fact use more water than disposable over their lifetime, however, because we are on baby number two and some of our secondhand nappies are on baby number four that impact is reduced  
  • We don’t use the eco modes on the dishwasher or the washing machine. I find they don’t clean as well and I’m left with food all over the dishes and dirt on the clothes
  • Our garden isn’t drought tolerant, we have two veggie patches that require plenty of water and other fruiting/ornamental trees and shrubs that are not designed for hot Aussie summers. We also have not been very good at ensuring our garden is as water efficient as possible

*For a comprehensive list of water saving techniques head to www.smartwatermark.org.

So far I’ve only looked at our direct water useage. This doesn’t take into account all the water required to produce all the stuff we need, like the 140 L for the coffee I’m currently sipping, or the water required to produce the a roll of toilet paper (140 L), or the water needed to manufacture the pair of jeans and t-shirt I dressed myself in this morning (20,000 L), or the glass of wine I drank last night (120 L), or a juicy beef steak (3,800 L), or worse yet a 100 g bar of chocolate (2,400 L).


Moving Forward

While our household target is well below 155 L per person, perhaps I need to scrutinise the way I use the toilet (perhaps installing a bidet?) and pay more attention to the food and drinks we consume, opting for those that have a lower water footprint.

I plan to create a more drought tolerant garden, with plants that are suitable to the climate over ornamental foreign plants. I’ll try to cut down shower time (as a mum of two young kids every time I get in there it feels like I’m visiting a day spa so this may be my biggest challenge) and make small tweaks to daily life like using less dishes and washing clothes less often.

Over all, as stated in The Conversation, “without the increase in greenhouse gas emissions, terrestrial water storage would remain generally stable in most regions”. So it’s one thing to reduce our water consumption but the root of the problem is reducing our emissions.


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