Low Water Pressure In The Shower

Almost everyone who calls us about shower pressure actually has a flow rate problem, and the two need different solutions. Pressure is the force behind the water, flow is how many litres arrive each minute, and it is flow that makes a shower feel good. Before spending money on a pump or a new valve, spend five minutes measuring what you have and checking the usual restrictions. In a lot of homes the fix costs nothing more than a descaled head and a fully opened valve.

Measure first

Take a two litre jug, hold it under the shower head at full flow and time it. Two litres in twelve seconds is ten litres a minute, which gives a perfectly decent shower. Six litres a minute feels weak. Then do the same at the bath tap with the head removed from the equation. If the bath tap is strong and the shower is weak, the restriction is in the shower itself. If both are weak, it is the supply or the system.

Quick wins, in order of likelihood

1. Descale the head. Soak it overnight in a limescale remover, or rub the rubber nozzles clean if it has them. This is the single most common cause of gradual weakening.
2. Check the flow restrictor. Many heads and hoses ship with a small plastic washer that limits flow. On a low pressure system it can often be removed.
3. Open the isolating valves fully. Screwdriver slot valves on the shower feeds are frequently left half closed after work.
4. Replace a kinked or narrow hose. Cheap hoses with a small bore throttle a handset noticeably.
5. Clean the valve filters. Thermostatic valves have small strainers on the inlets that clog with debris.

System causes that need more work

• Gravity fed with little head height. A loft tank only a metre above the shower gives very little pressure. Raising the tank is rarely practical, so a shower pump is the usual answer on this system type.
• Old 15mm runs with many tees. Long pipe runs feeding several outlets lose flow badly. Rerouting a dedicated feed during a refit makes a big difference.
• A combi at its limit. A combi boiler can only heat so many litres a minute. If yours is a lower output model, no valve or head will exceed that figure.
• Unvented cylinder set low. Pressure reducing valves and expansion vessels need servicing, and a tired vessel gives poor performance.
• Partially closed stop tap. The main stop tap for the house is sometimes never fully reopened after work elsewhere.

Choosing a shower that suits low flow

If the system genuinely cannot deliver more, choose fittings that make the most of what there is. A concentrated head with fewer, well aimed jets feels far stronger than a wide rain head at the same flow. Avoid twin outlet arrangements that split flow between a head and a handset. On gravity systems, a low pressure rated head is designed for exactly this and will feel much better than a mains rated one.

What not to do

Do not fit a booster pump to a mains fed combi or an unvented cylinder. That is against water regulations and can pull the pressure down for neighbours as well as damaging your own system. Do not drill out restrictors in an electric shower, which relies on a set flow rate to reach temperature. And be wary of anyone offering a pump as a first answer before measuring anything.

Getting it designed right

When we plan a bathroom we check the flow and pressure at survey and specify the shower around the result, rather than fitting something impressive looking that the house cannot feed. Where the pipework is the limit, we run a dedicated feed while the walls and floors are open, which is far cheaper then than later.

Ask us to check yours

We survey water systems as part of every bathroom quote across Stoke-on-Trent and the surrounding towns. Tell us what your shower is doing using the enquiry form, or read more about our bathroom fitting service. Free survey, fixed written price within 24 hours.

Common questions