Leak Detection – Non-Destructive Hidden Leak Tracing

Leak detection is a technical diagnostic service aimed at identifying the precise location of a hidden water leak without blindly dismantling structures. It is not a repair job or an opinion – it is a series of measurements that provide the client with a specific point or narrow zone where the pipe is damaged. This precision is precisely why leak detection is commissioned: every square metre of floor or wall opened without reason later incurs restoration costs that often far exceed the cost of the diagnostic itself.

The most common situation is that a client has the consequence but lacks the cause. There's a yellow stain on the neighbour's ceiling, the carpet in the hallway is warped, the tile grout in a bathroom corner is constantly dark, or the heating system pressure drops every few days. All these are symptoms that can stem from various sources: a pressure pipe, drainage, underfloor heating, a hole in the waterproofing, condensation, or even rainwater entering from the façade. The primary task of leak detection is to rule out these possibilities and identify the correct system.

Another typical reason is financial. Water meter readings increase without explanation, the apartment association's balance doesn't add up, the difference between the main meter and the sum of apartment meters grows each month. Such a continuous, yet invisible, flow rate is almost always a leak underground, in the basement, or near a riser. Here, leak detection immediately provides a financial benefit – every month the search is delayed costs real money.

The third reason is insurance and evidence. If damage has already occurred, the insurance company or apartment association will ask where the water came from and whose area of responsibility that location falls under. We provide a proper invoice and a description of the found leak location for the work performed, which can be submitted to both the association and the insurance company.

• Damp patch on the ceiling, wall, or floor with an unknown source
• Heating system pressure drops, requiring constant refilling
• Water meter moves when all taps are closed
• Unexplained high water bill or discrepancy between main and apartment meters
• Warm spot on the floor – a typical sign of an underfloor heating circuit leak
• Mould, peeling paint, or constantly damp grout in a specific area
• Neighbour reports water damage that needs to be substantiated

A hidden leak develops slowly and reveals itself in several stages. The earlier a symptom is recognised, the cheaper both the detection and the repair will be. The earliest sign is usually not dampness, but the system's behaviour: heating system pressure won't hold, the water heater switches on more frequently than usual, the water pump in a private house activates at night without consumption, or circulation becomes noisy. These are all indicators that water is escaping from a closed system.

The next stage is noticeable dampness. The air in the bathroom or kitchen area remains humid, tile grouts don't dry, silicone darkens, parquet begins to lift at the edges, or laminate joints swell. This is often accompanied by an odour – a musty, earthy smell that appears before mould is even visible. If moisture has reached the surface finish, the leak has usually been ongoing for weeks.

The third stage is visible damage: a patch on the neighbour's ceiling, dripping from a light fitting, a water bubble under a paint layer, salt efflorescence on a wall surface, or peeling plaster. Here, the question is no longer *if* a leak exists, but only *where* it is precisely coming from. It is in this phase that we are most often called – and it is here that accurate leak detection offers the greatest savings, as it determines how much finishing needs to be demolished.

Warm spots on the floor deserve special attention. If an area in a room with underfloor heating is noticeably warmer, or if a warm stripe appears on the floor with radiator heating, this is almost always an indication of a heating pipe leak within the screed. Heating water is warm, so a thermal camera detects such a leak particularly well – and such cases are usually resolved most quickly.

• Heating system manometer drops below 1 bar within a week
• Grout and silicone remain constantly dark and damp
• Musty smell behind a cabinet, under a drawer, or in a bathroom corner
• Parquet or laminate lifts at the edges without visible reason
• Warm spot on the floor, not related to sun or appliances
• Water pump or boiler activates at night when no one is using water

There is no single universal leak detection device. Each method only detects certain types of leaks under specific conditions, which is why we always combine them. For a typical site, we use two to four methods: the first narrows down the area, the second confirms or refutes, and the third determines the exact point. Only when at least two independent measurements point to the same location do we recommend opening the structure.

Leak detection begins with a phone consultation. We ask what exactly is visible, when it started, if any repairs have been done, if the heating system pressure is dropping, and if the water meter is moving when taps are closed. These answers alone significantly narrow down possible causes and allow the technician to bring the correct set of equipment.

On-site, the work begins with an inspection and clarification of the system's logic: where risers, manifolds, shut-off valves are located, where pipes run, and when construction work was last carried out. We inspect visible damage and measure the extent of moisture. Then, we perform a pressure test to rule out entire sections, and only then proceed to precise diagnostics with a thermal camera and acoustics.

If two methods point to the same area, we physically mark the leak location on the floor or wall and discuss the next step with the client. We explain how large an area needs to be opened, what the estimated repair scope is, and if there's an alternative – for example, closing off the pipe and rerouting it along a new path without opening the old location.

In most cases, we also perform the repair immediately: we open the marked spot, replace the damaged section, restore the connection, re-pressurise the system, and monitor for sustained pressure. The work concludes with a control measurement and instructions on how to dry the structure before the finishings are restored.

• 1. Phone consultation and symptom mapping
• 2. Site inspection, system diagram, and moisture measurement
• 3. Pressure test and exclusion of intact sections
• 4. Precision diagnostics – thermal camera, acoustics, trace gas if needed
• 5. Leak location marking and solution coordination
• 6. Opening, repair, pressure check, and handover

The type of property determines both the choice of method and the organisation of work. The same symptom can mean a very different scope of search in a flat versus a private house.

Domestic water piping is a constant pressure system. Leaks there are often louder, faster, and acoustically well audible, but a very small drip can last for months without significant pressure drop because the pump or city water constantly compensates for the loss. This is where monitoring the water meter with closed taps provides the best answer: if the dial moves, water is escaping somewhere in the system.

A heating system is a closed loop where the water volume is fixed. Every drop that escapes lowers the manometer reading. Therefore, detecting a heating leak is fundamentally simpler – simply monitoring the pressure and isolating circuits is sufficient. Heating water is also warm, which means a thermal camera detects it in the structure much better than a cold water leak.

Underfloor heating is a separate case. Circuits are long, embedded in screed, and there are usually several of them. Our usual approach is to close all circuits at the manifold and pressure test them one by one – this quickly reveals which circuit isn't holding pressure. Only then do we use a thermal camera to pinpoint the leak on that specific circuit. This sequence prevents opening the wrong circuit.

Drainage is a pressure-free system, so pressure testing and acoustics do not work. Diagnostics there involve a filling test and video inspection, searching for cracks, displaced couplings, or incorrect gradients. A drainage leak is usually identified by its smell and periodicity – moisture appears precisely when water is being used.

• Domestic Water: constant pressure, good acoustic signal, meter check
• Heating: closed loop, pressure drop is the most reliable indicator
• Underfloor Heating: circuit-by-circuit pressure testing before thermal imaging
• Drainage: filling test and video inspection, not pressure test

The most frequent question we get on the phone is whether the floor and tiles really need to be broken up. The answer is usually encouraging: properly conducted diagnostics narrow down the leak location so precisely that often only a 30-50 cm wide area needs to be opened. This means one or two tiles or a limited section of screed, not removing the entire room's covering.

Complete avoidance of opening is possible in some cases. If the leak is located in a shaft, manifold cabinet, space under a bathtub, behind a suspended ceiling, or in a utility room, then access through a hatch or panel removal is sufficient. Sometimes, an old pipe can also be left within the structure, and a new line can be routed along a different path – for example, along the edge of the ceiling, in a channel, or behind a skirting board. Such rerouting is often cheaper than cutting concrete and restoring finishes.

Opening is unavoidable when the pipe is located within monolithic screed or concrete and a confirmed leak point exists. In such cases, it is crucial that the opening is made at the correct spot and in one go. The most expensive option for the client is not the opening itself, but multiple mistaken openings made based on assumptions without measurement – unfortunately, we see such cases quite often.

We never recommend opening a structure based on the result of a single method alone. If the thermal image and acoustic findings do not coincide, we continue searching – we add sectional pressure testing or trace gas. Only a confirmed point justifies any destructive work.

• Shaft, manifold cabinet, suspended ceiling, and utility room – usually without demolition
• Narrow opening of 30-50 cm after a confirmed point
• Pipe rerouting as an alternative to concrete cutting
• Monolithic screed – opening necessary, but only at one spot

The most common mistake is waiting. A small drip doesn't disappear on its own – it enlarges the opening, saturates insulation, and eventually reaches the neighbour. Delaying for weeks usually turns a simple pipe repair into a moisture damage restoration project, the cost of which is in a completely different league.

Another mistake is to open the floor where a damp patch is visible. Water travels in the structure along a slope and emerges at the lowest or least dense point – this is not the leak location, but the exit point. This is why we always measure, rather than relying on the location of the patch.

A third mistake is to dry and finish before the cause has been found. A dryer will remove moisture, but if the pipe continues to leak, everything will recur in a few months – this time under new flooring. The correct sequence is always: find the cause, repair, dry, restore.

The fourth mistake is to leave the situation undocumented for insurance and the apartment association. Photos taken before repairs begin, thermal images, and measurement results are later the only evidence of where the water came from. We document this during the work, as it saves the client money in the long run.

Most hidden leaks don't start suddenly – they are preceded by a process that lasts for years. Old galvanised pipes corrode from the inside, press connectors installed with the wrong tool start to seep over time, and excessively hard water damages seals. Knowing the system's age provides a good forecast: metal piping 30-40 years old is already at the end of its lifespan, regardless of whether it's leaking now or not.

The simplest preventative step in a flat is to install shut-off valves so that water can be quickly turned off, and to check the water meter once a year with all taps closed. In a private house, it's worth adding a water leak sensor and an automatic shut-off valve near the main tap – this device pays for itself many times over with one prevented emergency.

For heating systems, the best prevention is regular monitoring of the manometer. If water needs to be added more than a couple of times during the heating season, it's not normal, but a hidden leak that should be located before it saturates the screed.

During major renovations, it's always advisable to photograph all pipe routes before they are covered. Such photographic evidence significantly shortens subsequent leak detection and saves both time and money.

• Check the water meter once a year with all taps closed
• Install a water leak sensor and automatic shut-off valve
• Monitor the heating system manometer throughout the heating season
• Photograph pipe routes before they are covered
• Routinely replace metal piping that is 30+ years old

The cost of leak detection is determined by three components: time spent, the number of methods used, and the complexity of the site. A small flat where the heating system pressure is dropping and there is no underfloor heating is usually a quick job. A large private house, where multiple systems, manifolds, and outdoor lines need to be inspected, requires more time and often multiple measurement sessions.

Site complexity increases due to lack of access, unknown pipe routes, multiple previous repairs with different materials, and situations where the system cannot be freely shut off – for example, an operational commercial property or an apartment building where shutting off water affects many residents. We clarify these factors during the initial phone call to provide a realistic time estimate.

It is always worth comparing the cost of diagnostics with the alternative. Blind opening means demolition, debris removal, new screed, new tiles, and finishing – usually many times more expensive than accurate measurement. The same applies to waiting: restoring saturated insulation and a neighbour's ceiling far exceeds the cost of leak detection.

We provide an exact price before starting work, once we have reviewed the site's symptoms and scope. There will be no unexpected additions to the bill – if an additional method is required, we will agree on it separately.

The first step is to stop the water supply to the suspected area. Close the main valve for the flat or the shut-off valve for the respective branch. If it's a heating system, do not add more water until you have noted down the manometer reading – the speed of pressure drop is valuable information for us.

The second step is to document the situation. Photograph the damp patch, write down the water meter reading and time, and take another photo an hour later. This immediately tells you if the leak is active and how large it is. If water has reached a neighbour, notify the neighbour and the apartment association in writing.

The third step is to avoid opening anything yourself. Very often, tiles are broken where water emerged, and only then is a technician called – the result is damaged finishes and still an unlocated leak. Call us before you demolish anything; often, we can already tell you over the phone what the most likely source is.

If water is actively flowing and damage is increasing by the minute, it is an emergency – our dispatcher operates 24/7, and in Tallinn, a team usually arrives within 30-60 minutes, and in Harjumaa within 1-2 hours.

• Close the main valve or the valve for the affected branch
• Note the water meter reading and heating system pressure
• Photograph the damage before any action
• Do not open the structure yourself without measurement
• In case of active flow, call the emergency number immediately