Every child now knows that we should use our drinking water sparingly. Lower water consumption is easy on the wallet, the sewage treatment plant, and the environment.

Average drinking water consumption has fluctuated around 123 liters per citizen per day (approx. 45 m³/a) for years. If you want to know how much water you consume individually, it is worth taking a look at your annual consumption bill.

Guidelines for your water consumption are:

• up to 30 m³/a = low consumption (80 l/d)
• 30 - 45 m³/a = average consumption (100 l/d)
• more than 45 m³/a = high consumption (120 l/d)

[m³/a = cubic meters per year; l/d = liters per day]

These values are determined as follows:

1. Read the annual water consumption bill (in m³/year).
2. Divide the water consumption by the number of people living in the household.
3. This gives you the specific water consumption of your household (in cubic meters per person per year m³/a).

If you want to reduce your personal water consumption, the following tips may help:

• Take a shower instead of a bath. A shower uses up to 70% less water and energy than a bath.
• Turn off the water while soaping up in the shower.
• Fix dripping taps and leaky toilet flushes as soon as possible, otherwise you will waste a lot of water in the long run.
• When brushing your teeth, it is best to use a toothbrush glass or turn off the tap while brushing.
• Buy toilet cisterns that hold less than six liters. Use the economy button.
• Do not rinse dishes under running water.
• Single-lever mixers prevent a lot of water from being wasted when adjusting the temperature.
• Retrofittable flow regulators reduce water consumption in shower heads and sink faucets.
• When purchasing water-consuming appliances, pay attention to the water consumption specifications.
• Check your systems and water consumption regularly.
• Set your dishwasher and washing machine to the water-saving program.
• Only run washing machines and dishwashers when they are full.
• Collect rainwater for watering your garden.
• Water plants only when it is cool, if possible. Otherwise, a lot of water will evaporate unused.

Saving hot water pays off

Saving water can also help reduce energy consumption. On average, 13% of a household's energy costs are spent on producing hot water. So using hot water sparingly is good for the climate and your household budget.

Two examples for a two-person household illustrate the various ways in which savings can be made:

Assuming that a German two-person household that heats its water with an electric instantaneous water heater consumes an average of 1,300 kilowatt hours of electricity per year, this costs around 375 euros. If the water is heated by a gas boiler, the average annual consumption is 1,800 kilowatt hours. This corresponds to operating costs of around €150. (Source: /www.co2online.de; calculated using the following prices: electricity: 29 cents per kilowatt hour, gas: 7 cents per kilowatt hour (including basic price))

In example 1, the two-person household has a modern, fully electronic instantaneous water heater for hot water. This is an efficient device that allows the temperature to be set precisely to the degree. Here, too, savings can be made, but this time on consumption: Assuming that the two residents shower for seven minutes at a temperature of 39 degrees Celsius on 330 days a year, this results in electricity costs of around 350 euros. If they shower for just one minute less and at one degree less every day, they can save around 370 kilowatt hours of electricity and thus just under 107 euros in a year.

Example 2 also involves a two-person household, this time in an apartment building with central hot water supply. Here, an energy savings account is used to monitor energy consumption for hot water heating over the course of a year. The results show that the household consumes 2,800 kilowatt hours for water heating. This is well above average. The residents decide to make small changes to their behavior. They now use cups when brushing their teeth, turn off the water when washing their hands, and shower for one minute less than usual. They also equip their household with flow restrictors and a water-saving shower head. After one year, the energy savings account shows a significant reduction in consumption. The figure now stands at 2,200 kilowatt hours. The savings amount to the equivalent of around 40 euros.

If you would also like to reduce your personal hot water consumption, the following tips may help:

• Pay attention to your shower temperature and time
• Turn off the tap while soaping up
• Wash your hands with cold water
• Descale your fittings and systems regularly
• Wipe with cold water
• Wash your laundry at the lowest possible temperatures

Don't know how much hot water you use on average? Then it's best to do an individual water check.