Low Water Pressure at Home? 8 Causes and How to Fix Them
Weak showers, a geyser that takes forever and taps that dribble when someone flushes: low water pressure is one of the most common complaints we hear. The good news is that most causes are easy to find. Work through the checks below before you spend money, and if the problem is the supply itself, a booster pump fixes it for good.
First, measure your pressure
Screw a cheap pressure gauge onto a garden tap close to the meter or tank and open the tap fully. Most homes are comfortable at 2.5 to 3.5 bar at the taps. Below about 1.5 bar, showers feel weak, especially upstairs. You can also time a bucket: a good shower gives about 8 to 12 litres a minute.
If the pressure is fine at the garden tap but weak inside the house, the problem is in your plumbing. If it is low at the garden tap too, the supply is the problem.
8 common causes of low water pressure
1. Your water comes from a tank
Water flowing down from a tank only gains about 0.1 bar for every metre of height. A JoJo tank on a 3 m stand gives roughly 0.3 bar, far below what a shower needs. Any home running from a tank, rainwater or borehole storage needs a booster pump.
2. Low municipal pressure
Pressure drops at peak times, in high-lying areas and when the municipality throttles supply during water shortages. If the gauge reads low at the meter, the supply is the cause.
3. A valve that isn’t fully open
Check the stopcock at the meter and the isolating valves under the geyser and basins. A valve left half closed after plumbing work is a surprisingly common cause.
4. Blocked aerators, shower heads or strainers
Limescale and sand block tap aerators and shower heads over time. Unscrew them and soak them in vinegar. Many geysers also have a strainer on the inlet that clogs.
5. The geyser’s pressure control valve
If only the hot water is weak, look at the geyser. Its pressure control valve limits hot water pressure, and older low-pressure geysers give weak hot water no matter what. A plumber can tell you which valve you have. Never remove it to gain pressure: more than about 4 bar can damage geysers, mixers and toilet valves.
6. A leak
Close every tap and watch the water meter. If it still turns, water is escaping somewhere, which costs you pressure and money.
7. Old or undersized pipes
Long runs of thin pipe and old galvanised pipes that have rusted inside both restrict flow, so pressure collapses as soon as two taps are open.
8. Your existing booster pump needs attention
If you already have a booster pump, check the pressure setting, look for air leaks on the suction side and check the pressure tank. A flat tank bladder is the most common reason a pump switches on and off all the time.
How a booster pump fixes low pressure
A booster pump takes water from your tank or supply and pushes it into the house at a steady 2.5 to 3.5 bar. Size it by how many taps run at the same time:
- Flat, cottage or 1 bathroom: 0.37 kW
- 2 to 3 bathrooms, single storey: 0.55 to 0.75 kW
- 4 or more bathrooms, or a double storey: 1.1 kW
- Guest houses, small farms or irrigation: 1.5 to 2.2 kW
Our booster pump size guide walks through the full calculation. The easiest option is a booster pump combo: pump, controller and fittings assembled and tested, ready to connect. Choose a flow controller for a compact setup, a pressure switch with a pressure tank for the most reliable one, or a VSD pump for quiet, constant pressure.
Frequently asked questions
What is good water pressure for a house?
About 2.5 to 3.5 bar at the taps. For a double storey, allow roughly 0.3 bar extra for every 3 m the highest shower sits above the pump.
Can I connect a booster pump straight to the municipal line?
Many municipalities don’t allow a pump connected directly to the mains. The usual setup is a storage tank that fills from the municipal supply, with the booster pump after it, which also keeps water flowing during water cuts (see our water outage backup guide). Check your municipality’s by-laws.
Why is my hot water pressure lower than my cold?
Usually the geyser’s pressure control valve, a blocked geyser inlet strainer or an older low-pressure geyser. Fix the geyser side first; a booster pump only helps if the supply to the geyser is low.
Will a booster pump work during load shedding?
Not without power. Run it from an inverter, or use a solar booster such as the SQB250 solar booster pump combo.
Get the right pump the first time
Tell us how many bathrooms you have, whether it’s a single or double storey, and where your water comes from. WhatsApp us on 012 881 1962 and we’ll match a pump for you, free, with delivery anywhere in South Africa. Or browse all booster pumps.