Low Water Pressure in Shower — Diagnose and Fix
A weak shower is usually one of five things. In order of frequency: limescale in the head, flow restrictor, low mains pressure, gravity-fed with no pump, or blocked inline filter.
Step-by-step method
1. Descale the shower head
Unscrew, soak overnight in cider vinegar or citric acid. Solves 60% of weak-shower complaints.
2. Remove the flow restrictor
Every UK electric shower has a plastic washer with a small hole in the water inlet. Pop it out (or drill 1mm larger) for a stronger flow.
3. Check mains pressure
Fit a pressure gauge to any outside tap. Below 1 bar and you'll never get a good shower without a pump.
4. Fit a shower pump (gravity-fed only)
For homes with a loft tank, a 1.5–2.0 bar twin impeller pump (Salamander, Stuart Turner) doubles shower flow. £250 + fit.
5. Clean the inlet filter
Behind the flexi hose at the valve — a small mesh filter. Rinse under a tap, refit.
Frequently asked questions
Can you fit a pump to a combi shower?+
No — combi boilers self-limit flow. Pumping upstream can damage the boiler and voids warranty. Combi-fed showers need a pressure-boost pump on the mains cold, or a mains booster set for the whole property.
What pressure is required for a mixer shower?+
Minimum 1 bar; ideally 1.5–3 bar. Gravity-fed systems below the loft tank often struggle.