Low Water Pressure in an HDB Flat: Causes, Fixes and Who to Call

It's your block if neighbours' water is weak too, and your flat if only your taps are.

1. Check the lift lobby for PUB or town council notices about water works.
2. Ask a neighbour on your floor, and one a few floors down, whether their water is weak.
3. Open the kitchen tap and a basin tap fully. If every tap is weak, the supply to your flat is restricted.
4. Check that the stopcock at your flat's PUB water sub-meter, just outside your main door or in a service cupboard, is fully open.
5. After a water cut, run a cold tap for a minute to clear any trapped air.
6. Time how long the shower takes to fill a 5-litre pail at full flow, on cold and then on hot.

If 5 litres takes more than about 67 seconds (under 4.5 litres a minute), the flow is weak; a healthy shower takes about 43 to 67 seconds. New 2- and 3-tick shower mixers must reach 4.5 litres a minute when tested at 1.5 to 5 bar. On the top floors, low pressure from the rooftop tank can cause it on its own; lower down, suspect a restriction.

Call the town council if the whole block is weak, PUB for a burst main, and a plumber if only your flat is affected.

HDB tells residents to inform the town council when low pressure comes from a booster pump fault (HDB: Pipes). For water supply breakdowns, call your town council's 24-hour Essential Maintenance Service Unit (EMSU) line; each town council has its own number, on its website or notice board.

A shower that's weak on its own usually has a gritty shower head, a kinked hose or a clogged mixer cartridge. Weak only on hot points to the water heater.

1. With the heater switched off, unscrew the shower head from the hose and run the shower without it.
2. If the flow improves, soak the head in white vinegar for an hour and brush the nozzles.
3. Unscrew the tap aerators, rinse out any grit and refit them.
4. Straighten the hose, and replace it if it's flattened or kinked.
5. Compare the mixer with the basin tap; if only the mixer is weak, its cartridge is likely clogged.

Instant water heaters need a minimum flow to switch on, typically about 2 litres a minute in makers' manuals. Below that, the heater stays cold or cuts out mid-shower. The heater's inlet filter, at its stop valve, can clog with grit. Never open the heater's cover: there are no user-serviceable parts inside. Some makers also warn against fitting flow-control devices on the heater's outlet.

A storage heater runs at your supply pressure and doesn't boost it, so a weak hot side points to its inlet valve or strainer. For heater faults, see water heater services, water heater not getting hot, and instant vs storage water heater.

Remove whatever is restricting the flow: open the valves fully and clean or replace the head, hose or cartridge. Adding a pump isn't the answer.

Singapore's Water Supply Regulations make it an offence to install or use a pump or fitting in a way that affects, or is likely to affect, the pressure or efficient supply of PUB's water (Public Utilities (Water Supply) Regulations). Don't fit a booster pump, or have one fitted, on your flat's supply. If the whole block is weak, the town council's pumps and tanks are the fix.

The same Regulations require exposed shower taps and mixers supplied since 1 Apr 2019 to be rated at no more than 7 litres a minute (concealed mixers aren't covered), so no shower head adds water. A head with a small face and fine nozzles concentrates the flow into a firmer spray; a large rain shower in an HDB flat spreads it thin.

In older flats, rusted pipes can narrow until the whole flat is weak. The pipes need replacing by a PUB Licensed Plumber.

SG QuickFix diagnoses low shower pressure from $80. The low shower pressure repair service covers the head, hose and mixer.

The price goes up when a mixer or heater has to be changed. Replacing old or concealed pipes needs a PUB Licensed Plumber and isn't covered by these prices. Each job is priced separately. For an accurate price, send a 10-second video of the shower at full flow, your pail-test time, and whether neighbours are affected. See also the full plumber price list for Singapore.