Non-invasive leak detection using acoustic equipment, thermal imaging and pressure testing. We find the leak AND fix it — in one visit, without unnecessary excavation.
Most leaks are invisible — buried under concrete slabs, inside walls, or underground. Modern leak detection uses non-invasive technology to pinpoint the exact location before any ground is broken.
We use three primary methods: acoustic listening equipment that amplifies the sound of water escaping from a pressurised pipe; thermal imaging cameras that detect temperature differences caused by water saturation; and pressure testing that isolates sections of pipework to confirm which line is leaking.
A slab leak occurs when a water pipe beneath your concrete slab develops a crack or pinhole. Signs include unexplained water bill increases, warm spots on the floor, damp patches, or running water sounds when all taps are off.
Using acoustic equipment, we pinpoint the leak to within centimetres without breaking up your slab. Repair options: cut a small access hole to repair the section, or reroute the pipe above the slab to bypass the damage entirely.
Underground supply lines can develop leaks from corrosion, tree root damage, ground movement, or age. In Northern Sydney's established suburbs — Wahroonga, Turramurra, Pymble — many homes still have original copper or galvanised supply lines that are approaching end-of-life.
We locate the leak using acoustic detection and pressure testing, then repair or replace the damaged section. For older lines prone to multiple failures, we recommend full replacement with modern poly pipe.
Swimming pool leaks and irrigation system leaks can waste enormous volumes of water and cause ground subsidence. We pressure-test pool plumbing lines and irrigation zones to identify which line is leaking, then pinpoint the exact location.
Many leak detection companies only locate the leak — they hand you a report and leave you to find a plumber. O'Brien Plumbing does both. Our licensed plumbers carry the detection equipment AND the repair tools, so in most cases we find the leak and fix it in a single visit.
We use multiple detection technologies depending on the leak type and location:
| Method | How It Works | Best For | Accuracy |
|---|---|---|---|
| Acoustic Listening | Amplifies the sound of pressurised water escaping through a pipe wall or joint | Slab leaks, underground supply lines, mains leaks | Within 10–30 cm |
| Thermal Imaging | Infrared camera detects temperature differences caused by water evaporation or hot water leaks | Wall and ceiling leaks, underfloor heating, hot water pipe leaks | Identifies affected zone (30–50 cm) |
| Pressure Testing | Isolates sections of pipework and monitors pressure drop to identify which line is leaking | Confirming a leak exists, isolating which pipe is affected | Identifies the line, not the exact point |
| Tracer Gas | Injects a safe gas (hydrogen/nitrogen mix) into the pipe; gas escapes at the leak point and is detected at the surface | Very small leaks, pool plumbing, gas-tight confirmation | Within 5–15 cm |
| Moisture Mapping | Electronic moisture meters map the extent of water migration through walls, floors and ceilings | Insurance documentation, identifying full extent of damage | Maps affected area (not leak source) |
We typically combine 2–3 methods to triangulate the exact leak location before making any cuts or excavations.
Typical cost ranges for leak detection and repair in Northern Sydney:
| Service | Cost Range | What's Included |
|---|---|---|
| Leak detection (locate only) | $250 – $500+ | Multi-method detection, written report, location marked |
| Leak detection + repair (same visit) | $350 – $800+ | Detection, excavation/access, pipe repair, pressure test |
| Slab leak repair (after detection) | $500 – $1,500+ | Concrete cutting, pipe repair/reroute, reinstatement |
| Pool leak detection | $300 – $600+ | Pressure test all lines, tracer gas, location report |
| Insurance leak report | $180 – $350 | Written report with photos, moisture mapping, cause documentation |
Source: O'Brien Plumbing cost guide (obrien.com.au). On-site diagnostic included. Fixed prices confirmed before any work starts. 7-year workmanship warranty on repairs.
Locating hidden leaks in Northern Sydney’s varied building stock and terrain requires a methodical, safety-first approach. Our leak detection process is designed to be non‑invasive, evidence‑based and minimally disruptive — we combine acoustic listening, thermal imaging, tracer gas and pressure testing with traditional plumbing know‑how so you only open walls or slabs when absolutely necessary.
When initial scanning narrows the location, we confirm with controlled tests that do not require demolition.
Only after gathering converging evidence from thermal, acoustic and pressure/tracer tests do we mark the exact access point. Our goal is to minimise demolition — often a 100–200mm core or targeted section of skirting is all that’s required instead of full floor removal.
Before any intrusive work we provide relevant Safe Work Method Statements (we operate under 17 SWMS) and ensure the work respects heritage and strata requirements. We are licensed, insured and hold a gas fitting licence where required.
Hidden leaks can start small but cause major damage if left unattended. On Northern Sydney properties, where older plumbing and mature gardens are common, watch for these early warning signs:
We maintain transparent, practical pricing for our leak detection service operating from our Hornsby base. Our diagnostic fee structure reflects the specialist equipment, technician training and comprehensive reporting required to locate concealed leaks without unnecessary demolition.
$815 including GST
This comprehensive diagnostic service includes:
This fee covers typical residential properties within our Northern Sydney service area (Hornsby and surrounding suburbs listed below). It ensures a full diagnostics package aimed at locating leaks without demolition.
Occasionally, more advanced or extended diagnostics are necessary to locate particularly elusive leaks — for example, hidden slab leaks beneath thick concrete, deep underground water mains, or complex multi‑storey strata risers. O’Brien carries tracer gas, pressure testing rigs and specialist pipe locators; if these confirmatory techniques are required beyond the standard package, we will:
Please note: our standard $815 package often includes tracer gas or short pressure tests where they are required to confirm locations; for extensive, time‑consuming tracer gas surveys, extended pressure testing, or multi‑level commercial diagnostics, additional charges may apply — always quoted up front.
High‑density strata blocks, commercial buildings and heritage properties commonly need tailored approaches and scheduled access. For these jobs we provide a formal quote after an initial site inspection and can offer after‑hours diagnostics to minimise disruption. Depending on the complexity, fees will be quoted specifically for the job.
We provide 24/7 emergency response from our Hornsby base for urgent leaks that risk significant water damage. Emergency attendance and rapid diagnostics are available — please call (02) 9477 1519 and advise it’s an emergency. Emergency diagnostic pricing is handled on a case‑by‑case basis and will be discussed when you call.
Leak detection techniques are the same in principle, but scale, documentation, access and disruption considerations differ between residential and commercial (including strata) properties. Our Hornsby team tailors the approach to suit the property type and stakeholder requirements.
Northern Sydney’s combination of older homes, steep sandstone blocks, and dense tree cover means proactive maintenance can prevent many leaks or identify them early. Here are targeted prevention strategies for Hornsby‑area properties.
Check your water meter monthly. Early detection of meter movement when no water is being used is a simple, low‑cost way to spot underground or slab leaks.
Book a yearly non‑invasive inspection with thermal imaging to check for hidden hot water or cold water leaks, especially in homes built in the 1950s–1970s where copper and galvanised pipes may be corroding.
Mature gardens in Northern Sydney can invade sewer lines and lateral drains. Keep root systems away from sewer lines where possible, and organise regular sewer checks if you have large trees near lateral drains. If you suspect root ingress, contact a licensed plumber before it causes a break or blockage.
Heavily treed properties experience frequent gutter blockages which lead to roof water tracking and timber decay. Clean gutters at least twice yearly (more if you have pines or eucalypts) and ensure downpipes discharge away from the foundation to prevent water pooling against slabs or retaining walls.
On sloping sandstone blocks, make sure surface water is directed away from the house. Poor surface drainage can accelerate rising damp and cause water to track into basements or lower level walls.
Excessive mains pressure accelerates pipe wear in older copper and galvanised systems. Fit a pressure regulator and have system pressure checked during annual servicing.
Hot water leaks can be masked behind cupboards or within wall cavities. Regular servicing of hot water systems and lagging of exposed hot water pipes reduce the risk of unnoticed deterioration.
Small drips can signal bigger problems. Repairing minor leaks early prevents corrosion, structural damage and mould growth — and reduces the chance of costly slab repairs later.
Accurate leak location depends on the right tools and a technician who understands how to interpret the data. From our Hornsby base we deploy industry‑grade equipment chosen for effectiveness in Northern Sydney’s building and ground conditions.
FLIR thermal imaging reveals temperature differences caused by moisture or escaping hot water behind finishes. In heritage and older homes, thermal imaging allows us to inspect large areas of wall or ceiling without intrusive openings, making it ideal where finishes must be preserved.
Acoustic devices detect the characteristic sound of water under pressure. Correlators compare sound signals at two points along a pipe run to calculate the leak location — a technique proven for slab leaks and underground lateral leaks. These devices are invaluable in Hornsby’s mature garden environments where leaks can occur under thick turf or mulch.
Hydrogen/nitrogen tracer gas is introduced at low, safe concentrations into a pressurised pipe and detected at the surface using sensitive sniffers. This method is particularly useful for pinpointing leaks beneath concrete slabs or deep underground where acoustic signals are attenuated.
Pressure testing isolates pipe sections and applies controlled pressure to confirm integrity. A controlled pressure drop locates which zone contains the leak and removes guesswork when planning remedial works.
Moisture meters quantify moisture content in timber and wall finishes and map the exact extent of water intrusion. Pinless scanners allow wide area scans without surface damage — critical when assessing heritage joinery or plasterwork.
Electronic pipe locators trace the path of buried metallic and detectable plastic pipes. In combination with acoustic and thermal methods they provide a map of underground services so we can avoid other utilities when accessing a leak.
When hidden water threatens your Northern Sydney property, you need diagnostics that are accurate, documented and minimally invasive. O’Brien combines specialist equipment, cross‑trade knowledge and strong safety practices to deliver reliable outcomes.
Non‑invasive leak detection uses diagnostic tools such as thermal imaging, acoustic listening devices, tracer gas and pressure testing to locate leaks without opening up large sections of wall, floor or slab. The aim is to identify the exact access point so that repairs are limited to the smallest, most targeted openings.
Yes. The tracer gas we use is a low‑concentration hydrogen/nitrogen blend. When used by trained technicians it is safe and non‑toxic. The gas is applied in controlled quantities during testing and detected at the surface with sensitive sniffers. We will explain the process and safety steps before proceeding.
Most residential diagnostics are completed within 2–4 hours from arrival, depending on property size and complexity. Commercial, strata or difficult underground leaks can take longer. The initial assessment and non‑invasive scans are typically fast; confirmatory tracer gas or extended pressure testing will add time and will be quoted before we proceed.
We aim to avoid demolition. Our multi‑modal approach (thermal imaging + acoustic correlation + pressure tests + tracer gas when needed) narrows the location to a small access point. Only when all non‑invasive methods point to a precise spot do we recommend a targeted opening, which is often a small core or panel instead of full floor removal.
Yes. The comprehensive leak detection service ($815 inc GST) includes a detailed written report with annotated thermal images, acoustic readings and recommended next steps. We format reports to support insurance or strata documentation as required.
Yes. Slab leaks are a common issue in Northern Sydney; we combine acoustic correlation, thermal imaging and tracer gas to locate slab leaks. In many cases we can pinpoint a 100–200mm access point, avoiding full slab demolition.
We plan access in advance and use non‑destructive techniques wherever possible. For heritage properties we liaise with owners and, where required, heritage officers to ensure repairs conform with preservation requirements. Our 17 SWMS ensure a documented safety plan for each job.
Yes. After diagnosis we can provide quotation options for repair. Because we offer both plumbing and roofing, we can coordinate repairs across trades if the leak involves roof flashings, gutters or structural timbers. Repairs are only undertaken with your prior approval.
Mature tree roots in Northern Sydney commonly invade sewer laterals and supply lines. We use acoustic and tracer gas methods to locate underground leaks. For sewer issues we can advise on safe remediation paths and liaise with landscapers regarding root management. Where excavation is required, we mark utilities and plan repairs to minimise garden disruption.
Yes. We understand that commercial buildings and strata blocks need minimal disruption. We offer after‑hours diagnostics and can schedule testing outside peak times. We provide full documentation for strata committees and building managers.
Our Hornsby base serves the Northern Sydney region with targeted experience in the unique challenges of these suburbs. If your property is in any of the areas below, our technicians are familiar with the local housing stock, terrain and vegetation patterns that influence leakage problems.
If you are outside these suburbs but still within Northern Sydney, call (02) 9477 1519 — we’ll confirm coverage and advise the best approach. For emergencies, our 24/7 response can be mobilised from our Hornsby base quickly to limit water damage.
To arrange a non‑invasive leak detection inspection or to speak to a technician about symptoms you’re seeing, call O’Brien Hornsby on (02) 9477 1519. Our $815 comprehensive leak detection includes thermal imaging, acoustic testing and a full written report — the first step to finding and fixing hidden leaks without unnecessary demolition.
We use acoustic listening equipment combined with thermal imaging to pinpoint the leak to within centimetres without breaking up the slab.
Yes. Our licensed plumbers carry both detection equipment and repair tools. We find and fix in one visit.
Common signs: unexplained water bill increases, running water sounds when taps are off, warm spots on floors, damp patches, a spinning water meter, or musty smells.
Hornsby, Wahroonga, Turramurra, Gordon, Pymble, Asquith, Mt Colah, Berowra, Brooklyn, Thornleigh, Pennant Hills, Cherrybrook, Galston, Dural and surrounding areas.
Many home insurance policies cover the cost of locating a leak and the resulting water damage. We provide documentation for your insurer.
Suspect a Hidden Leak? We'll Find It.
Non-invasive detection and same-visit repair across Northern Sydney.