How much water you use during a 20-minute shower will depend on what type of shower system – and in particular, showerhead – you have installed.
Low-flow showerheads will emit around two gallons of water per minute, equating to 20 gallons per 10-minute shower, and 40 gallons over the course of a 20-minute shower.
If a standard showerhead is fitted, it will use around an extra half a gallon each minute, accounting for a 25-gallon emittance every 10 minutes, or 50 gallons throughout a 20-minute shower.
*1 gallon = 4.54 litres.
