Pressure Reducing Valves

A pressure reducing valve lowers incoming supply pressure to a safer, more stable level for the property. When it sticks, wears or is incorrectly selected, pressure may become too high, too low or unstable.

Before you worry

A pressure reducing valve should not be adjusted simply because flow feels weak. The actual pressure and flow conditions must be measured first.

How to recognise the problem

• Pressure is much higher or lower than before.
• Pressure varies while water is being used.
• The valve hums, whistles or vibrates.
• Leaks recur downstream of the valve.
• Geyser or appliance valves discharge unusually.

Common causes

• Worn internal diaphragm or seat.
• Debris lodged inside the valve.
• Incorrect sizing or pressure range.
• Age, corrosion or scale.
• Upstream pressure changes.
• Poor installation or missing strainers.

What you can safely check yourself

• Locate the valve and record its markings.
• Compare pressure behaviour at different outlets.
• Check for visible leaks around connections.
• Arrange gauge testing before adjustment.

What you should never do

• Do not dismantle a pressurised valve.
• Do not turn adjustment screws without pressure readings.
• Do not replace it with an unmatched generic valve.
• Do not bypass required pressure control.

When to call a plumber

Call a plumber when pressure is unstable, the valve leaks or makes noise, or downstream components repeatedly fail.

How professionals solve it

The plumber measures upstream and downstream pressure under static and flow conditions, checks valve specification and installation, cleans or replaces the unit and verifies stable pressure afterwards.

How to prevent it happening again

• Keep upstream strainers serviceable.
• Test pressure periodically.
• Replace ageing valves before repeated failures.
• Use the correct valve size and pressure range.
• Protect exposed valves from damage.

Frequently asked questions