Water pressure, and why a new shower feels weak
2 July 2026 · 3 minute read
A shower head rated at 9 litres a minute is rated at 350 kPa. On a gravity fed system running at 150 kPa it will not deliver 9 litres a minute, and no head will.
Before choosing anything, find out what you have. A plumber can put a gauge on an outside tap in two minutes. Under 200 kPa, choose a head with fewer, larger nozzles and skip the rain heads entirely, or budget for a pump.
The second most common cause is a flow restrictor left in the arm from a previous fitting. It is a small plastic disc and it is free to remove.