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Why Airlocks Happen in Water Systems — And How to Prevent Them
Few things are more frustrating than turning on a tap or shower and being met with spluttering water, inconsistent pressure, or strange noises coming from the system. In many cases, the cause is something surprisingly common: an airlock.
At NT Cloke Pumps & Water, airlocks are one of the more frequent issues we diagnose across domestic, commercial, and multi-property systems. While they may seem like a minor inconvenience at first, recurring airlocks can signal deeper problems within the system and place unnecessary strain on pumps, booster sets, and pipework.
Understanding why airlocks happen — and how to prevent them — is key to maintaining a reliable and efficient water system.
What Is an Airlock?
An airlock occurs when air becomes trapped within a water system, preventing water from flowing properly through sections of pipework or equipment.
Because pumps and pressurised systems are designed to move water — not air — trapped pockets of air disrupt pressure balance and reduce system efficiency.
Airlocks can affect:
- Domestic plumbing systems
- Booster pump systems
- Heating systems
- Commercial water infrastructure
- Borehole and pressurisation systems
In some cases, they cause only mild disruption. In others, they can significantly impact performance and contribute to long-term wear.
Common Signs of an Airlock
Airlocks often produce symptoms that people initially mistake for low pressure or pump failure.
Typical signs include:
- Spluttering taps or showers
- Inconsistent water flow
- Sudden drops in pressure
- Gurgling or bubbling sounds in pipework
- Pumps running noisily or inefficiently
- Certain outlets losing flow completely
In larger systems, airlocks can even trigger pressure alarms or contribute to repeated pump cycling.
Why Airlocks Happen
There are several common causes of air entering a water system.
Poor System Design
Incorrect pipe gradients or poorly designed layouts can create areas where air naturally becomes trapped. This is particularly common in older systems or systems that have been modified over time.
Low Water Levels
Where water levels drop too low — particularly in tanks or borehole-fed systems — air can be drawn into the supply line and circulated through the system.
Leaks and Loose Connections
Small leaks or poorly sealed joints may not always release water visibly, but they can allow air to enter the system under certain pressure conditions.
Maintenance or System Draining
Any time a system is drained for servicing, repairs, or upgrades, air can become trapped when the system is refilled if venting isn’t carried out correctly.
Pump and Pressure Issues
Incorrect pressure settings or unstable pump operation can create turbulence within the system, encouraging air accumulation and inconsistent flow.
Why Airlocks Shouldn’t Be Ignored
Airlocks don’t just affect convenience — they affect performance.
When air is present in a pressurised water system:
- Pumps work harder to maintain flow
- Pressure becomes unstable
- Components experience additional wear
- Energy efficiency drops
Over time, recurring airlocks can contribute to:
- Increased pump cycling
- Noise and vibration
- Reduced system lifespan
- Higher maintenance costs
In commercial buildings, inconsistent water flow can also lead to complaints from tenants, guests, or occupants.
How Air Affects Pump Systems
Pumps are designed to move water efficiently and consistently. Air within the system disrupts this process and can create a condition known as cavitation.
Cavitation occurs when air bubbles collapse within the pump, creating shockwaves that damage internal components such as:
- Impellers
- Bearings
- Seals
Over time, this significantly reduces pump lifespan and performance.
Real-World Problems We See at NT Cloke
Our engineers regularly attend sites where recurring airlocks are linked to wider system issues, including:
- Booster sets drawing in air due to low tank levels
- Poorly vented systems after maintenance work
- Commercial systems with unstable pressure causing repeated air build-up
- Leaking joints introducing air into pipework
In many cases, the airlock itself is only the symptom — not the root cause.
Preventing Airlocks Properly
Preventing airlocks starts with proper system design and maintenance.
Key preventative measures include:
- Correct pipework installation and gradients
- Maintaining stable pressure levels
- Ensuring tanks and supply lines are properly managed
- Regular servicing and inspection
- Proper venting procedures after maintenance
For larger systems, automatic air vents and pressure management controls can significantly reduce recurring issues.
Why Professional Diagnosis Matters
Simply bleeding the system may temporarily remove trapped air — but if the underlying cause isn’t identified, the issue will often return.
At NT Cloke, we assess the full system to determine:
- Where air is entering
- Why it’s accumulating
- Whether wider pressure or design issues exist
This ensures long-term solutions rather than repeated short-term fixes.
FAQs
What causes airlocks in water systems?
Airlocks are usually caused by trapped air entering through maintenance work, low water levels, leaks, or poor system design.
Can airlocks damage pumps?
Yes. Persistent air within a pump system can lead to cavitation, increased wear, and reduced lifespan.
Why do my taps splutter randomly?
This is often a sign of trapped air moving through the pipework.
Can NT Cloke diagnose recurring airlock problems?
Yes — we identify both the airlock and the underlying cause behind it.
Struggling with spluttering taps or inconsistent pressure?
Recurring airlocks are often a sign that something deeper within the system needs attention. Left unresolved, they can reduce efficiency, increase wear, and place unnecessary strain on your pumps and pipework.
If you’re experiencing pressure fluctuations, noisy pipework, or recurring airlock issues, NT Cloke can help identify the cause and provide a long-term solution.
📞 0116 373 5496
📧 info@ntclokepumpsandwater.co.uk
🌐 www.ntclokepumpsandwater.co.uk
