What Causes High Water Pressure and Water Hammer in Buildings?

High water pressure and water hammer are common concerns in building plumbing systems, particularly in existing and high-rise buildings where water pressure needs to be properly managed across different parts of the system.

When pressure is too high or changes rapidly, building management may experience problems such as noisy pipework, pressure fluctuations, recurring pipe failures or stress on plumbing components.

A Pressure Reducing Valve (PRV) is one of the components that may be used to manage water pressure within a building plumbing system. However, a PRV should not be considered in isolation. The overall pressure management arrangement should be assessed to understand the actual condition of the system.

1. What Is High Water Pressure?

High water pressure occurs when the water pressure within a section of a plumbing system is higher than the pressure required for that part of the building.

In a building plumbing system, pressure requirements can vary depending on factors such as:

Building height
Water supply arrangement
Pumping system
Pressure zones
PRV settings
Existing pipework
Building plumbing configuration

If pressure is not properly managed, excessive pressure may place additional stress on pipework, valves, fittings and other plumbing components.

2. What Is Water Hammer?

Water hammer is a pressure surge that can occur when water flow changes suddenly within a pipework system.

For example, when a valve is closed quickly, the moving water can experience a sudden change in momentum, resulting in a pressure wave travelling through the pipework.

Depending on the building plumbing system, water hammer may be associated with:

Sudden valve closure
Rapid changes in water flow
Pump operation
Pressure fluctuations
Poorly controlled pressure
Existing pipework conditions

The actual cause should be investigated based on the system configuration rather than assuming that one component is responsible.

3. What Problems Can High Water Pressure Cause?

Excessive or poorly controlled water pressure may contribute to problems within an existing plumbing system.

Possible concerns include:

Pipe leakage
Joint or fitting problems
Valve damage
Pressure fluctuations
Recurring pipe failures
Increased stress on existing pipework
Noisy plumbing systems

However, recurring pipe problems do not automatically mean that high pressure is the cause.

The existing pipework, supports, joints, valves, pumps and other relevant components should also be inspected.

4. What Is the Role of a PRV?

A Pressure Reducing Valve (PRV) is used to reduce and control water pressure within a plumbing system.

In a building, a PRV may be part of the pressure management arrangement used to maintain an appropriate pressure downstream of the valve.

The actual PRV setting depends on the building's plumbing system and operating requirements.

A PRV that is incorrectly set, poorly maintained or not operating properly may affect pressure control within the system.

For this reason, PRV servicing should involve more than simply adjusting the pressure setting.

5. What Should Be Checked When Water Pressure Is Too High?

When a building experiences high water pressure or unstable pressure, several parts of the plumbing system may need to be investigated.

These may include:

PRV condition
PRV pressure setting
Upstream water pressure
Downstream water pressure
Pressure fluctuations
Pump operating conditions
Pipework condition
Valves and fittings
Pressure zones
Previous plumbing modifications

Pressure measurements at relevant points can help provide a clearer understanding of how the system is operating.

6. Can PRV Problems Cause Water Hammer?

A PRV can be part of a building's pressure management system, but water hammer can have multiple causes.

If water hammer is occurring, the investigation should consider the overall plumbing system, including:

PRV operation
Pressure conditions
Pump operation
Valve operation
Flow changes
Existing pipework
Pipe supports and connections

Simply replacing a PRV does not necessarily resolve every water hammer problem.

The cause needs to be investigated before deciding on the appropriate rectification works.

7. What Does PRV Servicing Involve?

Depending on the condition of the system, PRV servicing may involve:

Inspection

Checking the existing PRV and associated pipework.

Pressure Measurement

Checking pressure conditions upstream and downstream of the PRV.

Cleaning and Servicing

Inspecting and servicing the PRV where required.

Pressure Setting

Adjusting the PRV pressure setting according to the requirements of the existing plumbing system.

Calibration / Verification

Checking whether the PRV is operating at the required pressure condition.

Replacement

Where the existing PRV is damaged, worn or no longer suitable for the system, replacement may need to be considered.

The actual scope should be determined based on site conditions.

8. Why Is Pressure Management Important in Existing Buildings?

Existing buildings can have plumbing systems that have been modified, repaired or upgraded over time.

The current pressure management arrangement may therefore be different from the original building configuration.

Problems can occur when:

Existing pipework has deteriorated
Pumps have been changed
PRV settings have changed
Plumbing systems have been modified
Pressure requirements have changed
Different components are operating together under different conditions

This is why pressure problems in an existing building should be investigated as a system, rather than looking at one component alone.

9. What Should Building Management Do When Pressure Problems Keep Recurring?

If a building experiences recurring high water pressure, unstable pressure or water hammer, building management should consider:

Checking the existing pressure readings
Inspecting the PRV
Checking PRV settings
Reviewing pump operating conditions
Checking relevant pipework and valves
Investigating pressure fluctuations
Reviewing previous plumbing modifications
Determining whether servicing, adjustment, calibration or replacement is required

A proper assessment can help identify whether the issue is related to the PRV, pumping system, pipework or another part of the building plumbing system.

How A TECH Approaches Existing Building Plumbing Problems

A TECH CONSTRUCTION SDN BHD is a Specialist Plumbing Engineering Contractor specialising in Existing & High-Rise Buildings across Kuala Lumpur, Selangor, Cyberjaya and Putrajaya.

We provide engineered plumbing repair, maintenance, rectification, replacement, refurbishment and modification solutions for existing building plumbing systems.

Our work includes PRV servicing, pressure management, pressure checking, PRV calibration and related plumbing rectification works, depending on the existing site condition.

For buildings experiencing high water pressure, unstable pressure or recurring water hammer concerns, A TECH can assess the existing plumbing system and investigate the PRV, pumping system, pipework and related components to determine the appropriate maintenance or rectification approach.