Why is my shower pressure weak?

Why is my shower pressure weak when other taps are fine?

When only one shower is weak, the cause is usually at that outlet or its heater, not the building supply: the shower head and its regulator, the hose, or the instant heater feeding it.

Measure the flow first so you can tell whether each fix helps. Using PUB's method, collect the water for 6 seconds and multiply the litres by 10 to get litres per minute. Do the same at a tap. If the tap flows well and the shower reads much lower, the problem is at the shower.

Clogged shower head and hose

Debris in the head or its regulator can cause low shower pressure. HDB says water regulators in taps and showers can be removed and cleaned with a brush and water if the flow is slow, and Ariston lists a twisted hose and debris in the hand shower among the causes of low flow.

1. Unscrew the shower head. Turn the shower off and unscrew the head from the hose by hand.
2. Clean the regulator. Take out the water regulator and scrub it and the inside of the head with a brush under running water.
3. Straighten the hose. Undo any twists so the hose hangs freely.
4. Refit and test. Refit the regulator and the head, then repeat the 6-second test.

If you would rather replace the head or hose, PUB's simple plumbing works list lets a handyman replace or remove a shower hose or a showerhead connected to a tap.

Heater filters and flow switches

If an instant heater feeds your shower, Ariston lists these causes of low flow: a stop-cock valve that is not fully open, low inlet pressure, a jammed mesh filter, debris in the hand shower or a twisted hose. Check that the stop-cock valve is fully open first.

Rheem's manual for its electric instant heaters says to clean the inlet filter net when flow drops. Clean it as the manual describes, or ask the service centre. The manual also says the heater needs at least 1.5 litres per minute to trigger its flow switch and switch on, so a weak shower can also run cold. If the heater still does not heat or shows an error code, stop there: the manual says a flow switch or electrical fault should be checked by a competent electrician or Customer Service. See instant water heaters for more on these units.

Flow restrictors and water-saving fittings

A thimble on a tap or shower hose reduces excessive flow, and PUB recommends thimbles for taps rated below 2 ticks. A thimble lowers the flow at that outlet by design. If you think one is cutting your shower flow too far, ask a plumber to check it.

HDB says flow can also be adjusted at the water-meter adjustment valve in the service duct outside the flat.

Rain shower requirements

If you find your rain shower weak or not hot enough, check the heater as well as the head. Joven says a storage heater may be undersized for a large rain shower plus a basin, and Joven's sizing table matches storage heater capacity to the outlets it serves.

The table covers storage heaters only, not instant heaters. Heater size affects how much hot water you get, not the water pressure, so a rain shower with weak pressure still needs the checks above and a plumber if it stays weak. If the water does not heat at all, see our guide to no hot water.

When to call a plumber or the Town Council

If every tap in your flat is weak, HDB says to inform the Town Council if a booster pump fault causes low water pressure, and to clear an air lock by running the tap for a while to let the air out. For problems across the whole home, see low water pressure at home.

If one outlet stays weak after you have cleaned the head, regulator and any heater filter, call a licensed plumber.

PUB's simple plumbing works list lets a handyman replace or remove any tap or mixer, a shower hose or showerhead connected to a tap, and any pipe between a stop valve and an instantaneous water heater. Repairing or replacing any other water pipe, concealed or exposed, is work for a PUB Licensed Plumber, and since 2018 it has been an offence to engage a plumber not licensed by PUB for regulated works. See tap replacement for tap and mixer jobs, and what needs a licensed plumber for other work.

The price depends on the job: see plumbing costs.

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