Using an average number of 8 litres per minute from a typical shower head, by reducing your shower length by 4 minutes per day would save 14000 litres per year. In addition to save water, you also save the energy required to heat water to the shower temperature.
Energy and water savings
Spending one minute less in the shower each day will save 15€ off the energy bills each year, per person.
References and best practices
Research into saving water the experiences and perceptions of customers and their households: