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From small streams come great rivers – decreasing water consumption starts with little changes

There is a relatively large amount of clean water in relation to the population in Finland. The reserves of clean water are, however, limited, and wastewater processing consumes a lot of energy. This is why there has been increased attention paid to water use in recent years, and water consumption habits have taken a turn for the better. At Turku Student Village Foundation, the tenants’ water consumption is very near the Finnish average, but there is still room for improvements compared with other student housing foundations. Yet it is possible to decrease water consumption with small changes.

In early 2021, SOA (the Finnish Associations of Student Housing Organisations) carried out a comparison between different student housing communities and water consumption was one of the studied areas. In this comparison, TYS ranked near the top compared with other student housing communities. Being high on this list is not a so-called good thing for TYS, rather, we should aim for median consumption – that is, 115 litres of water per resident per day.

What makes up the total water consumption then? People’s use of water varies greatly according to their current situation in life. Those living alone typically use considerably less water than a family of four when we examine consumption per apartment and per tenant. On average, Finns consume around 120–150 litres of water while the objective is between 100–120 litres per day. Most of the water consumption comes from washing, as much as 45 % of total consumption. In the shower, the target flow rate is 12 litres per minute, so a 15-minute shower can consume as much as 180 litres of water. Thus, we can decrease our water consumption considerably by observing the amount of water we spend on washing.

Another means of really impacting out water consumption is by keeping an eye on the water fixtures and fixing potential leaks. A leaking water fixture, such as a toilet, can consume as much as two litres of water per minute. This naturally depends on the fixture and leakage. By reacting quickly to leaking water fixtures, we can save several litres of clean water. Here’s an example: a water fixture that leaks two litres per minute drains away 2,880 litres of clean water in a day, 20,160 litres per week (7 days), 86,400 litres per month (30 days), and 1,051,200 litres per year (365 days).

By decreasing our water consumption, we can also directly affect other consumption of energy, as producing warm water for home use also takes up heating energy. In the water bill, the share of wastewater is often higher than that of clean water. According to the website of Motiva – a sustainable development company run by the state – a 15-minute warm daily shower costs about 450 euros per year, while a 5-minute shower will lower this sum to 150 euros. These calculations assume 10 c/kWh for the price of energy and 3.4 euros/m3 for the price of water. So, water consumption has a large role to play also in terms of energy efficiency. When water consumption is high, the energy consumption average is slightly higher at the same time. This is because 30–40 % of service water is warm water, and warm water is about three times more expensive than cold water when we take into account the use of energy in heating the water. By saving warm water we can save nature.

During the autumn and via the 1.5-degree lifestyles campaign by the City of Turku, TYS has urged everyone to consider their water consumption in terms of the time they spend in the shower, and asked all tenants, staff members, and everyone else in Turku to take on the five-minute shower challenge. I tried this challenge at home and found that five minutes is enough to wash oneself properly. I urge everyone else to try this out too – get in and out of the shower in five minutes. If you turn off the water while still washing, subtract the pauses from the total time.
You can also observe your water consumption habits in other chores around the house, such as when doing the washing-up. You can find many good tips for this on the foundation website, and I recommend trying them out if you are interested in decreasing your water consumption easily. Small streams make great rivers, and even small savings in a large enough number of people will have considerable implications for energy efficiency.

Toni Pohjavirta
maintenance engineer