The Green Tau: issue 49

19th August 2022

Conserving water effectively.

This year we are feeling the effects of climate change more acutely, with a series of heat waves, a lack of rainfall and now a drought.  As hot and dry summers will be an ongoing feature of climate change, so too will water shortages and droughts. 

Part of the equation lies with how much water we consume and when, and how much water we can store. Part of the dilemma is that the time when we consume most water is in the summer months when  the chances of restocking depleted water supplies is most limited. When  it is hot and there is no rain, we quickly use water we have previously stored to water gardens, to irrigate crops, to provide drinking water for animals and people, to fill swimming pools and paddling pools etc. And as many of us have experienced, the water we had stored (domestically in water butts) has not been enough to keep our gardens green. There has been much discussion in the press about water companies not investing enough in new reservoirs. 

Is collecting and storing more water the only solution? Building reservoirs is expensive and happens at the loss of someone else’s ‘backyard’. Cleaning and distributing water (and subsequently treating what is discarded) incurs its own energy cost and the greater the volume, the greater the cost. Should we instead be looking to reduce the demand side of the equation?  

According to CCW, the Consumer Council for Water, the average person in the UK uses 152 litres of water a day. A washing machine uses about 50l per load, a five minute shower 40l (more for a power shower), 10-14l for the dishwasher and each flush of the loo can use 10l.  Very quickly you can see how that 152l of water disappears!  And this is without including a sprinkler for the lawn, a hose to wash the car or a power jet to clean the drive. 

Yes, we can reduce the amount of water we use. We can change to taps that use less water by produce a spray. Ditto for shower heads. We can adjust toilet cisterns to use less water per flush. We can opt for washing appliances that use less water. We can turn off the tap when washing hands and teeth. We can bathe less often and wash clothes less often – saving energy as well as water. We can plant our gardens with drought tolerant plants and cut the lawns less often. We can install more water butts, and even install systems to collect and recycle grey water. 

Leaks from water pipes – whether that is within a property, or out in the street – account for 113 litres per property per day according to CCW. Thames Water puts its leakage rate at a staggering 24% of the water it supplies. Sometimes leak go unnoticed because the water is leaking into the subsoil. Keeping an eye on our water meter should alert us to any leaks that occur on the consumer side of the pipes.

Yet households only account for a small fraction of the water we consume in the UK. The data below ⬇️ comes from the  WWF Water Footprint report https://waterfootprint.org/media/downloads/Orr_and_Chapagain_2008_UK_waterfootprint-vol1.pdf 

73.6% of the UK’s water is used in farming. 

17.9% is used by industry, and 

8.5% is used by households. 

Many of us are probably not aware how much water is used in farming. About a third of agricultural water is used for livestock, primarily as drinking water. A lactating cow needs 100+ litres a day, a farrowing sow, 30l and a beef animal 20l. Further water is used for washing/ cleaning dairy parlours, stock sheds and yards; for processing and cooling milk; and for disease control such as sheep dips and foot baths. (https://warwick.ac.uk/fac/sci/lifesci/wcc/research/resources/wateruse/technology/livestock.pdf)

Water for arable farming is primarily used for irrigation of outdoors in-field crops and undercover or protected, crops. Field crops requiring irrigation are primarily vegetables including sugar beet,  peas, beans etc (potatoes account for 54% of water consumption), sugar beet, orchards and other fruits such as strawberries. Grains and grasses only occasionally need irrigation. Protected crops include  (edibles such as salads, tomatoes, cucumbers, lettuces, peppers, herbs, celery, and aubergines; and ornamentals such as pot plants, bedding plants and indoor cut flowers. (https://www.nfuonline.com/archive?treeid=141830)  Water is also needed for spraycrops with pesticides and herbicides.

Just as domestic users of water can make savings by using more efficient equipment and appliances, so too can agricultural users. Just as gardeners can reduce their demand for water by swopping to drought tolerant plants, so too farmers can look to grow less water-greedy crops or drought tolerant varieties. But when it comes to providing drinking water for livestock, the only way to achieve reductions in water consumption would be by reducing stock numbers.  

A pressing issue both in the UK and globally,  is food waste. In the UK WRAP estimates that 3.6 million tonnes or  7.2%, of all food harvested is lost each year. 4% is classified as surplus which is food that would go to waste were it not diverted for use as animal food or other bio-based products. 3.2%  is pure waste, of which horticultural crops make up 54% of the total, cereals 30%, livestock 8% and milk 8%. (https://wrap.org.uk/resources/report/food-waste-primary-production-uk)  Such food waste may arise became the crop is damaged whilst growing in the field (pests and/ or weather), because supply exceeds the market demand, or because the product is the wrong shape/ too large/ too small, or because there is a lack of available labour to harvest the crop. 

On top of this primary level of waste, there are issues with food waste during processing, on the shop floor and in the home. WRAP estimates that a further 9.5 million tonnes of food is wasted of which 70% is wasted in the home. The most frequently thrown away foods are potatoes, bread and milk, whilst in total fresh vegetables and salad makes up 24% of the total.

So far  I have focused on the consumption of water in the UK, but as the WWF Water Footprint report goes on to demonstrate, when we import food and other items we are in essence importing the output of  someone else’s water. There are some products that we cannot – climatically – grow in this country such as cocoa and coffee. There are others, such as strawberries and tomatoes which have a longer growing season when grown elsewhere – say in Spain – than if grown here. However if these products come from areas where there are water shortages, our consumption of the same may be exacerbating that problem. As consumers we need to be conscientious in understanding the environmental costs of what we buy. When we buy Spanish strawberries are we endangering ecosystems in Spain? There has been a number of reports this year about the extraction of water by some strawberry growers that is adversely affecting the wetlands in the Doñana national park. (https://www.theguardian.com/world/2022/feb/08/bitter-fruit-strawberry-boom-water-plan-raises-fears-for-spanish-wetlands?CMP=Share_iOSApp_Other and https://www.theguardian.com/world/2022/mar/22/uk-supermarkets-urge-andalucia-against-huge-strawberry-farm-expansion?CMP=Share_iOSApp_Other)

On balance, whilst we should certainly save water in the home, we can do far more to safeguard water supplies and thus avoid water shortages, by rethinking what and how we eat. Eating less meat and dairy produce. Eating what’s in season, including the small/ large or wonky. Buying and cooking only what we need.