A tap that starts spitting and spluttering when opened is one of the most common minor nuisances in apartments and detached houses in Tallinn and Harjumaa, prompting residents to wonder if something is broken, if water quality has deteriorated, or if it's a sign of danger.
In reality, the cause is usually quite simple and harmless – air has entered the plumbing system, which is then expelled with the water when the tap is opened. This creates the characteristic spluttering, spitting sound, and sometimes foamy water, which might seem alarming at first glance, but is actually a physical phenomenon that typically resolves quickly.
In this guide, we'll explain in detail why air enters the plumbing, how to safely and quickly remove it yourself, the role of the aerator or tap nozzle mesh, and when spluttering water should make you vigilant and prompt you to call a specialist.
We'll also look at specific situations – post-water outage, first-time filling of a new apartment or house water system, properties with booster pumps, and specific water heater and mixer tap cases – so you can quickly identify your situation and know what to do.
What Exactly Happens When Air Enters the Plumbing System?
A water supply system is typically a closed system, entirely filled with water under pressure, where air should not be present. However, if air enters the system for any reason – for example, during pipe repairs, a water outage, or the installation of new equipment – air bubbles or longer air pockets form in the pipes.
When you then open a tap, the pump or water network pressure pushes not only water but also these air bubbles through the pipe. Air and water move together, and because air is compressible, it expands sharply at the tap nozzle, creating a characteristic spluttering, spitting, and sometimes rattling sound.
This is why the tap splutters – the mixture of water and air does not flow in a steady stream through the pipe, but in intermittent bursts, which are sprayed in various directions at the tap's small opening.
- A small amount of air causes a brief splutter lasting a few seconds, which quickly disappears.
- A larger air pocket in the pipe can cause several spluttering bursts in a row until all the air has been expelled.
- Sometimes, spluttering is accompanied by temporary cloudiness or a whitish tint in the water – this is also due to air bubbles, not dirt (read more below).
When Does Air Enter the Water System?
To prevent the problem or understand its recurrence, it's helpful to know the most common reasons why air enters the plumbing system in the first place.
- Water outage – when the water company temporarily shuts off the water supply (e.g., for pipe repairs), the pipe partially empties, and when the water network is restored, air enters the system, which must be expelled from the pipe before a stable flow is achieved.
- Plumbing repairs or replacement – if water pipes, shut-off valves, or fittings are replaced in a house or apartment, the system is inevitably opened, allowing air to enter, which must be removed from the system after the work is complete.
- Installation of a new water meter – during meter replacement, shut-off valves are closed and opened, allowing air to enter the system.
- Water heater or expansion tank maintenance and draining – if a water heater or hydro-pneumatic tank is drained for maintenance, it partially fills with air when reconnected, which then moves into the plumbing.
- First-time filling of the entire house's water system – in a new build or after a long period of inactivity (e.g., a summer cottage in winter), the entire plumbing system is filled at once, and air must flow out through all taps sequentially.
- Booster pump activation or restart – if a pump has been idle or there's been a power cut, air may remain in the plumbing when the pump restarts, before the pressure stabilises.
- Low water level in a well or tank – in detached houses where water comes from a well or borehole, if the water level is low, the pump may draw air along with the water, which is then carried throughout the house's system.
Tap Spluttering After a Water Outage – Is This Normal?
This is the most common situation that makes people worry about spluttering water, but it's also the most typical and predictable cause.
If the water company has announced a planned water outage for pipe repairs or maintenance, the affected pipe section partially empties, and when the water supply is restored, water is forced back into the pipe, passing through an air-filled section before being fully refilled.
In such a situation, it is entirely normal for the water from the taps to splutter, spit, appear whitish or contain air bubbles for the first few minutes or even hours after the water outage ends – this will disappear on its own once the plumbing system is completely refilled with water.
How long does this usually last?
In a small apartment with short pipe runs, normal water flow usually resumes within a few minutes after opening and closing the first couple of taps. In a larger house or building with longer plumbing, this can take up to several hours, especially if air needs to be removed from all floors and branches.
First-Time Filling of a New House or Renovated Apartment's Water System
In new builds and extensively renovated apartment buildings, the entire water system is drained before commissioning – meaning that upon first filling, the pipes initially contain only air, which the water must displace.
This process typically takes longer than a normal situation with a smaller air pocket, as the entire volume of the plumbing must be cleared of air. Builders and plumbers are aware of this process and usually run all taps, showers, and cisterns sequentially until the flow is smooth and the air is gone.
If you've just moved into a new apartment or a pipe replacement has been completed in your building, spluttering and spitting from the tap for a few days is a completely natural phenomenon that will disappear with active use within a couple of days.
Properties with Booster Pumps – How Does the Pump Affect the Air Problem?
Many taller apartment buildings and some detached houses use a booster pump to increase the pressure of water from the mains so that it reaches upper floors with sufficient force.
If the pump has been idle – for example, due to a power cut, maintenance, or a fault – it may draw air into the plumbing system when it restarts, before the pump system and water pipes are fully refilled with water and the pressure stabilises. In such a situation, spluttering and pressure fluctuations occur throughout the entire building, not just in one apartment.
If spluttering water occurs simultaneously in several apartments and the problem lasts for more than half a day, it's advisable to inform the apartment association or property manager – it may be necessary for a specialist to bleed the pump system directly at the pumping station.
- Single apartment, single tap – likely localised air, resolved by bleeding the tap.
- Multiple apartments simultaneously, including on different floors – likely a booster pump or riser issue, requiring a building-level solution.
The Role of the Aerator – Why Does the Tap Nozzle Magnify Spluttering?
An aerator, a small mesh part screwed onto the tap nozzle, is designed to mix the water jet with air to reduce water consumption while making the flow smoother and softer. In normal situations, an aerator helps make water use more economical and comfortable.
However, if there is excessive air in the plumbing, the aerator receives more air than it's designed to handle, causing the flow to become intermittent and spluttering – the aerator effectively amplifies the effect of air bubbles because it directs the exiting water jet through many small openings, which spray over a wider area when the air expands.
Without an aerator, the flow itself might still be intermittent, but spluttering is usually less noticeable because water flows through a larger, more uniform opening.
Can the aerator itself cause the problem?
Yes – over time, limescale, sand, and small dirt particles accumulate in the aerator's fine mesh, reducing its permeability. A partially blocked aerator can cause spluttering and an uneven flow even when there are no air bubbles in the plumbing – in this case, the problem won't disappear on its own but requires cleaning or replacing the aerator.
How to Distinguish Between Air-Induced Spluttering and a Blocked Aerator?
Since both situations result in a spluttering and uneven water jet, it's useful to know how to distinguish between the two causes.
- Air in the plumbing – spluttering is stronger in the first few seconds of opening the tap and gradually decreases or disappears if you let the water run for a few more minutes; often accompanied by whitish or milky water that clears within a few seconds.
- Blocked aerator – spluttering and an uneven flow are persistent and do not improve over time, the direction of the flow is uneven and sometimes sprays off-centre, and the problem occurs consistently every time you open the tap, not just after a water outage or repair.
- If the water flows evenly and strongly when the aerator is removed (the aerator is unscrewed by hand from the tap nozzle), the problem is definitely in the aerator, not the plumbing.
Why Does Water Appear White or Milky When Coming From the Tap?
Besides spluttering, many people notice that water appears cloudy, whitish, or milky when filling a glass. This often causes more alarm than the spluttering itself, but it is also a sign of air, not dirt.
The white tint occurs because small air bubbles are dissolved in the water – these scatter light and make the water appear cloudy. If you let a glass of water stand for a few minutes, the air bubbles will rise to the surface, and the water will clear from the bottom up, becoming normal, clear drinking water.
If the water remains cloudy even after standing for a few minutes and does not clear, it is no longer due to air but actual impurities or sediment – in such a case, it is advisable to contact the water company or a plumber regarding water quality (read more in our article on yellow water from the tap).
What Can You Do Yourself If Your Tap Is Spluttering?
In most cases, air can be removed from the plumbing easily and by yourself, without the need for a specialist. Proceed as follows:
- Open the tap at full power and let the water run for a few minutes – most air usually exits within the first 1–5 minutes.
- If your tap has an aerator, unscrew it and let water flow through the bare pipe – this allows air to exit faster and you can also check if the aerator needs cleaning.
- Start with the lowest tap in the house or apartment (e.g., the kitchen tap) and gradually move to taps on upper floors – air tends to accumulate at higher points and eventually exits with the water flow.
- Also check the shower and bath mixer taps, as these usually have wider outlets than basin taps and allow air to exit more quickly.
- If there is a water heater in the house, let the hot water from it run for a few minutes as well – the water heater itself may contain separate air pockets.
- If the water is cloudy, let a glass stand for a few minutes and see if it clears from the bottom – this confirms it was due to air.
How to Clean an Aerator If Spluttering Persists?
If spluttering doesn't decrease after a few minutes of running water and the flow remains uneven, it's worth unscrewing and cleaning the aerator.
- Unscrew the aerator from the tap nozzle by hand or, if necessary, with pliers (gently, wrapped in a cloth to avoid scratching the surface).
- Rinse the aerator under running water and remove any visible dirt and limescale.
- If limescale is stubbornly hardened, soak the aerator for half an hour to an hour in a diluted vinegar solution, which dissolves calcium deposits.
- If necessary, use a soft brush (e.g., an old toothbrush) to clean the fine mesh and opening parts.
- Rinse thoroughly and screw the aerator back onto the tap.
- If the aerator is very old, worn, or damaged, it's sensible to buy a new one – they are inexpensive and available in most hardware stores.
Does Spluttering From a Water Heater Tap Differ From a Cold Water Tap?
In households with water heaters, air can also accumulate within the hot water cylinder itself, not just in the pipes – meaning that spluttering from the hot water tap may last longer or be more intense than from the cold water tap.
This is particularly likely after water heater maintenance, sediment removal, heating element replacement, or a longer water outage during which the water heater has partially drained and then been refilled.
When should you be concerned about a water heater?
If hot water spluttering is accompanied by a continuous gurgling sound from the water heater itself, unusual odours, or sudden fluctuations in water temperature, it's advisable to call a specialist to check the water heater – this could indicate other problems, such as a faulty heating element (read more in our article on signs of a water heater heating element issue).
How Long Can Spluttering Last Before It's a Concern?
With a typical air problem, spluttering and cloudiness should disappear within minutes to a few hours, depending on the length of the pipework and the amount of air.
- Less than 15 minutes – completely normal for a single tap after a brief water outage.
- A few hours – normal for an entire house or long pipe run after a longer outage or repair.
- 1–2 days – possible when a new system is filled for the first time, but a decreasing trend should be observed.
- More than several days without improvement, or a problem that doesn't resolve even with careful bleeding and aerator cleaning – in this case, there's reason to suspect another problem, such as a pump malfunction, pipe damage, or a partially blocked shut-off valve, and you should contact a specialist.
Are the Causes Different in Apartment Buildings and Detached Houses?
Although air in the plumbing is the same physical phenomenon in both cases, the typical causes and solutions vary depending on the building type.
Apartment Buildings
In an apartment building, spluttering is often affected by the building's common pipework, booster pump, and maintenance carried out by the apartment association. If the problem occurs in several apartments simultaneously, the solution is usually building-wide and requires intervention from the association or manager. If the problem is only in your apartment, bleeding your own taps is usually sufficient.
Detached Houses
In detached houses, especially if water comes from a well or borehole, spluttering can also indicate a low water level in the well, causing the pump to draw air along with the water. If the well water level is low, the condition of the well should be checked, and if necessary, a well or borehole specialist contacted, as prolonged air intake can damage the pump.
When Is It Time to Call a Plumber?
Most spluttering cases are resolved by at-home bleeding and aerator cleaning, but there are situations when it's advisable to call a specialist.
- Spluttering does not improve within several days, despite regular bleeding.
- Spluttering is accompanied by a persistent drop in water pressure or unusual sounds in the pipes.
- Water remains cloudy even after several minutes of standing and does not clear.
- The problem occurs simultaneously in several apartments in an apartment building, indicating a building-level issue.
- In a detached house with a well, unusual pump noise or frequent on-off cycling occurs.
- You suspect pipe damage, for example, after construction work or ground movement on the property.
How can ToruFix help?
If needed, we will inspect the pipework and shut-off valves, professionally bleed the system at all points, clean or replace aerators and mixer taps, and determine if a larger technical fault, such as a booster pump malfunction or pipe damage, is behind the problem.
How to Prevent Spluttering in the Future?
While air entering the plumbing cannot always be completely avoided, some simple habits can reduce the frequency and severity of the problem.
- Clean aerators regularly, for example, a couple of times a year, to reduce limescale buildup.
- After a known water outage, first let the tap on the lowest floor run for a few minutes before using other appliances, such as a washing machine or dishwasher.
- If you plan a longer absence, close the main stopcock to prevent the system from draining and air entering.
- In a detached house, monitor the well water level regularly, especially during dry summer periods.
- In an apartment building, notify the property manager immediately if you notice spluttering in several apartments at once – early notification helps prevent long-term pump damage.