The flow from my mixer shower is less than I expected, what is the usual performance of a shower on a gravity system?

Flow rate from mixer showers varies depending on the available head of water and restrictions within the supply and valve. Commonly flow rate is between 3 and 5 litres per minute. To ensure optimum performance from a gravity fed mixer shower the following guidance should be followed: Use as few 90C elbows as possible, where possible use pulled bends. Use full way lever or gate valves, do not fit restrictive stop taps or 10mm internal bore service valves. Follow manufacturer recommendations regarding pipe size. Ensure the mixer is specified for low pressure application. Always flush out pipes before final connection to avoid debris blocking inlet filters.