What causes low water pressure in a house?
Low water pressure can have several different causes. Common examples include blocked tap aerators, restricted shower heads, faulty mixers, partially closed isolation valves, failing pressure limiting valves, ageing or restricted pipework, supply-pipe problems and low incoming mains pressure.
Because several different faults can produce the same symptom, replacing a part without first checking pressure and flow does not always solve the problem.
What is the difference between water pressure and water flow?
Water pressure is the force available within the water supply, while flow describes how much water can pass through the pipe or outlet over time.
A property may have reasonable static pressure but poor flow if pipework, valves or fixtures are restricted. This is why a useful diagnosis considers both the pressure available and how the system performs when water is actually being used.
Why is only one tap running slowly?
When only one tap has poor flow and the rest of the house performs normally, the issue is usually local to that fixture. The aerator may be blocked with debris, the mixer cartridge may be restricted, an isolation valve may not be fully open or there may be another local restriction.
In this situation, replacing the whole-house pressure limiting valve or installing a pump would generally not be the first step.
Why is my shower pressure low but the taps are fine?
A shower can have poor flow even when the rest of the property has adequate pressure. Shower heads can become restricted by mineral build-up or debris, flow restrictors can limit output and some mixers or filters can become partially blocked.
Comparing the shower with nearby taps helps determine whether the problem is isolated to the shower or part of a wider supply issue.
Can a pressure limiting valve cause low water pressure?
Yes. A pressure limiting valve is designed to control downstream water pressure, but a faulty, damaged or restricted valve can sometimes reduce the available flow more than intended.
The correct approach is to test the supply rather than assume the valve is faulty. If testing indicates that the valve is causing the restriction, replacement may restore normal performance.
Where is my pressure limiting valve?
The location varies between properties. It may be installed close to the water meter, near the point where the main water supply enters the house or elsewhere on the incoming cold-water line.
If you cannot identify one, that does not necessarily mean the property does not have one. JR can check the installation as part of diagnosing a whole-house pressure problem.
My whole house suddenly has low water pressure — what should I check?
First determine whether both hot and cold water are affected. If only the hot water is poor, the problem may be related to the hot-water system or hot-water pipework rather than the incoming supply.
If both hot and cold water are poor throughout the property, check whether there has been any known water-supply work in the area and, if practical, ask whether a neighbouring property has noticed the same thing. If neighbouring houses have normal pressure, the issue becomes more likely to be within your own water service.
Can low mains pressure be fixed?
Sometimes. The first step is confirming that the incoming mains pressure and available flow are genuinely inadequate and that the problem is not being caused by a restriction within the property.
Where the available supply is genuinely insufficient, a suitable pressure-boosting system may be considered. The correct solution depends on the property's plumbing arrangement and available supply conditions.
Do I need a water pressure booster pump?
Not automatically. A booster pump should not be the first recommendation simply because a customer describes the pressure as low.
JR first needs to establish whether the incoming supply is actually low. If the neighbours have strong pressure while your home does not, there may be a restriction or fault within your property's plumbing that should be addressed instead.
Why did my water pressure suddenly get worse?
A sudden change can result from a valve problem, debris entering a fixture, work on the local water network, a supply issue, damaged pipework or another restriction that has developed or moved.
Sudden whole-house changes are particularly useful diagnostically because they suggest something has changed rather than the property simply having always had limited supply.
Why has my water pressure gradually become worse?
Gradual deterioration can occur as aerators, shower heads, valves or pipework become increasingly restricted over time. Ageing components can also stop operating as they originally did.
Comparing different fixtures around the property helps determine whether the deterioration is localised or affecting the water supply more broadly.
Why does the pressure drop when two taps are used?
Some reduction is normal when multiple outlets are used at the same time, but a dramatic drop may indicate restricted flow, inadequate supply, small or problematic pipework or another limitation within the system.
Dynamic testing while fixtures are operating can provide more useful information than looking at static pressure alone.
Can old water pipes cause poor pressure?
They can. Ageing or internally restricted pipework can reduce available flow, particularly where the internal diameter has become reduced or where parts of the system are undersized for current demand.
This does not mean every low-pressure property requires repiping. Pressure and flow testing should be used to narrow down the likely restriction first.
Can a water leak cause low pressure?
A significant water leak can affect system performance, although many smaller leaks will not create an obvious pressure change at the taps.
If low pressure is accompanied by an unexpectedly high water bill, a constantly moving water meter, damp ground or unexplained water use, leak investigation may also be appropriate.
How does JR diagnose low water pressure?
The diagnosis begins with the symptoms: whether the problem affects one fixture or the entire property, whether both hot and cold water are affected, whether the pressure changes when several outlets are opened and whether neighbouring properties experience the same problem.
Depending on the property and symptoms, the plumber can then inspect valves and fixtures, check available pressure and flow and determine whether the likely cause is local to a fixture, within the property's water service or related to the incoming mains supply.
The objective is to identify the restriction before recommending parts or larger upgrades.
Can you replace a faulty pressure limiting valve?
Yes. If testing indicates that an existing pressure limiting valve is restricting the property's supply or is otherwise faulty, JR Gas & Water can recommend replacement with a suitable approved valve.
Pressure limiting valve replacement is also available as a separate bookable plumbing service where the required work is already known.
Can you install a booster pump?
JR Gas & Water supplies and installs water pumps for suitable applications. A booster pump may be appropriate where the available supply genuinely cannot provide the required property performance.
The system should first be assessed so a pump is not installed to compensate for a faulty valve, restricted pipe or another repairable plumbing problem.
Do I need to know what is causing the low pressure before booking?
No. Low pressure is a symptom, and homeowners are not expected to identify the exact plumbing component causing it.
Tell us whether the problem affects one fixture or the whole house, whether it affects hot water, cold water or both, whether it has always been like this or recently changed, and whether neighbouring properties appear to have the same problem. JR can then work through the likely causes and recommend the appropriate next step.
Low Water Pressure Questions Brisbane & Gold Coast Homeowners Ask
Why is my water pressure low all of a sudden?
Sudden low pressure may be associated with local water-supply work, a valve problem, debris or restriction, damaged pipework or another change to the system. If both hot and cold water have suddenly become poor throughout the property, whole-house diagnosis is recommended.
Why is only my kitchen tap low pressure?
If other fixtures work normally, the kitchen tap itself or its local water connections are more likely to be responsible. Aerators, cartridges, hoses and isolation valves can all affect flow.
Why does my shower have less pressure than my taps?
The shower head, flow restrictor, mixer or local pipework can restrict the shower independently of the rest of the house. Comparing the shower with nearby fixtures helps isolate the problem.
Can a pressure limiting valve reduce my water pressure too much?
Yes. A faulty or restricted pressure limiting valve can reduce downstream performance. Testing should be carried out before replacement so the valve is not blamed for a problem elsewhere in the system.
How do I know if my mains water pressure is low?
One useful clue is whether nearby properties experience similar pressure. However, the reliable way to assess the supply is to test the pressure and flow available at your property.
If my neighbours have good pressure, what does that mean?
It suggests the problem may be specific to your property rather than a general street-supply issue. The incoming service, valves and internal pipework should then be investigated.
If my neighbours also have low pressure, do I need a booster pump?
Not necessarily, but it makes low available mains pressure more plausible. The supply should still be tested before selecting a pressure-boosting system so the cause and required performance are understood.
Can I increase the water pressure myself?
Cleaning a blocked removable tap aerator or shower head may improve an isolated fixture, but whole-house pressure problems should be diagnosed before valves are adjusted, removed or pumps are installed.
Is high water pressure also a problem?
Yes. More pressure is not automatically better. Excessive water pressure can place additional stress on taps, valves, flexi hoses, appliances and hot-water components. Any pressure changes should remain appropriate for the plumbing system and applicable requirements.
Can I book low water pressure diagnosis online?
Yes. You can book JR Gas & Water's low water pressure diagnosis and repair service online without needing to know exactly what component is causing the problem.
Book Low Water Pressure Diagnosis & Repair Online
Whether you have one slow tap, a weak shower, poor pressure throughout the house or water flow that drops dramatically whenever several fixtures are used, you do not need to diagnose the exact fault before booking.
JR Gas & Water can test the system, identify the likely restriction and recommend the appropriate repair.
Where the cause is a separate repair such as a tap problem, pressure limiting valve replacement, leak repair or pressure-boosting system, the appropriate next step can be confirmed before additional work proceeds.
