Gravity-fed systems (cold tank in the loft, cylinder in the airing cupboard)
Pressure comes from the height difference between the tank and the shower. A first-floor shower under a loft tank often has very little head, which is exactly why it dribbles.
Realistic options: a shower pump sized to the outlet, a pumped shower unit, or raising the tank where the loft allows. A new mixer alone changes nothing.
Combi boilers
Flow is limited by the boiler's litres-per-minute rating and by incoming mains flow. Running a tap elsewhere while showering makes it obvious.
Worth checking first: a partially closed isolation valve, a scaled or clogged shower head, or a blocked filter on the shower valve. These are cheap and surprisingly often the answer.
Pumps cannot be fitted to a combi's output, so if the boiler is undersized the fix is a boiler or system change rather than bathroom work.
Unvented cylinders
These run at mains pressure and should give a strong shower. Weak flow here usually means an expansion vessel or pressure-reducing valve issue, or a restriction in the pipework - worth a plumber's check rather than a new shower.
Frequently asked questions
Will a rainfall head make my shower feel weaker?
On a low-pressure system, yes. Large rainfall heads need decent flow to feel good; on gravity systems they can feel like drizzle without a pump.
Can you fit a shower pump?
On gravity-fed systems, yes, sized to the outlets it serves and sited where noise is acceptable. Pumps are not suitable on mains-pressure or combi supplies.
Could limescale be the cause?
Frequently in hard-water areas like ours. Descaling the head and valve cartridge is the first thing to try and costs nothing.
Do you diagnose this during a bathroom quote?
Yes - we check the system type at survey so the shower we specify actually performs on your setup.
Next step
Tell us your system type and we will specify a shower that will actually perform on it.
Free quote • No pressure • Fast response