Common Causes of Low Water Pressure in Bayside Homes

We come across a lot of properties throughout Bayside Melbourne with excessively high water pressure, which can cause its own set of issues. On the other end of the spectrum, we also see plenty of homes struggling with low water pressure.

In most cases, low water pressure is not caused by low pressure from the street mains. There are usually internal issues within the property that restrict flow. Below, we explore the possible causes of low water pressure that we see most frequently.

1. Faulty Pressure Limiting Valve (PLV)

If your property has a pressure-limiting valve (PLV) installed at the water meter, this is often the first thing we check when diagnosing what causes water pressure to be low.

Over time, these valves can seize up, wear internally, or be incorrectly set. When that happens, they can restrict the pressure to well below what’s required for normal household use. While 500kPa is the maximum legal limit, a faulty PLV can drop pressure far lower than that.

Common signs include:

• Low pressure at all taps.

• Pressure drops further when multiple outlets are used.

• Sudden pressure loss rather than a gradual decline.

A simple pressure test at the meter tells us very quickly if this is the cause.

2. Corroded Pipework in Older Homes

Understanding what causes low water pressure in the whole house often starts with looking at the age of your plumbing. This is a very common approach for older Bayside homes that still have galvanised steel water pipes.

These pipes corrode internally over time, which narrows the internal diameter of the pipe and significantly reduces water flow. This doesn’t just affect pressure. It also causes water quality issues.

Common signs:

• Gradual loss of pressure over the years.

• Worse pressure at older fixtures.

• Brown or discoloured water coming from taps.

Unfortunately, this problem doesn’t fix itself. Once pipes are internally corroded, the only proper solution is renewing and upgrading the pipework to modern materials like copper or PEX.

3. Blocked or Failing Plumbing Fixtures

Sometimes, the issue isn’t the pipework at all.

Tap aerators, shower head restrictors, mixer cartridges, internal filters, and other plumbing fixtures can become blocked with sediment, scale, or debris. This is especially common in coastal areas and on hot water lines.

Common signs:

• Low pressure at one tap or shower only.

• Hot water pressure is worse than cold.

• Sudden pressure loss at a specific fixture.

If the problem is isolated to one outlet, this is often a quick and affordable fix once identified.

4. Partially Closed or Damaged Isolation Valves

Isolation valves can also cause low water pressure if they’re not fully open or have failed internally.

This can happen after renovations, maintenance work, or previous plumbing jobs where valves weren’t reopened fully. We also see valves clog internally over time, restricting flow even when they appear open.

This includes:

• Fixture isolation valves.

• Main house isolation valves.

• The water meter tap itself.

And yes, it happens more often than you’d think. Even the best of us have forgotten to fully reopen a water meter before and spent way too long wondering why the pressure suddenly dropped. It’s a simple thing, but it can make a big difference.

Why Low Water Pressure Should Be Checked Properly

Low water pressure isn’t just annoying. It can be a sign of:

• Failing valves

• Ageing or corroded pipework

• Hidden restrictions that may worsen over time

Identifying the cause early usually means a simpler and cheaper fix, rather than waiting until something fails completely. If you need a Bayside plumber to inspect your system, contact X1 Plumb today. Getting an expert opinion is the best way to restore your flow.