Slab Leak Detection

What This Service Does, and What It Does Not

This service assesses a suspected under-slab domestic supply leak and explains what the evidence does and does not establish. Leak Detection Plumber card remains the starting point when the source or route is generally unresolved. Slab Leak Repair card begins only after an under-slab domestic supply failure is confirmed. Hydronic, irrigation and other non-domestic systems require their applicable system and trade pathways.

How an Under-Slab Assessment Is Built

No fixed method sequence fits every slab, piping system or building. The assessment should select evidence and tests for the identified line, material, operating state, floor construction, access and safety conditions.

Review the concern and safety conditions. Establish when the symptom began, whether water is active, whether gas or electrical hazards may be present and which areas, meters or shutoffs can be approached safely. A safely accessible usage observation may add evidence, but it does not confirm the source or line by itself.

Identify the system and alternatives. Review visible piping, fixture and equipment layout, available plans, renovation history, radiant heating, in-slab ducts and other conditions that can explain warmth, sound or moisture. Domestic supply piping must be distinguished from hydronic, irrigation and other systems.

Gather accessible evidence. Note measured usage, moisture, temperature, sound, visible entry points and other relevant observations. The most noticeable symptom is not automatically the source, and no observation alone proves that a domestic supply line beneath the slab has failed.

Select suitable tests. Isolation, pressure or flow information, moisture observations and other methods may help narrow the possibilities. Method choice depends on the confirmed system, material, operating state, floor construction, access and current approved equipment. No method guarantees an exact location or a standard confidence radius.

Separate findings from inference. State which observations and test results are confirmed, what remains inferred, which areas were inaccessible and what uncertainty remains. Confidence may be limited by concealed construction, shared piping, unavailable isolation or competing heat and moisture sources.

Route the next step. The result may support monitoring, further investigation or a separate repair assessment. Detection evidence can inform a later decision, but it does not choose targeted repair, rerouting or broader repiping by itself.

Property Factors That Change the Assessment

Confirm whether the affected floor is slab-on-grade, a lower-level slab, a suspended slab or another construction type. Original construction era can frame questions, but it does not identify the piping or prove that an original route remains. Renovation history, visible pipe markings, available plans, floor finishes, shared systems and accessible entry points provide more useful evidence. Radiant heating, in-slab ducts, appliances and other equipment can also create warmth or sound, so those alternatives must be separated from a domestic supply-pipe concern.

Start With Safety

If water is active, check for gas and electrical hazards before approaching the area or operating a valve. Stay out of wet electrical areas and away from unstable finishes. Use only a safely accessible private shutoff, never force a questionable valve and never operate a municipal curb stop. Water-heater isolation and hydronic-system handling require property-specific professional guidance rather than a universal homeowner instruction.

Do not enter a restricted mechanical room, wet meter chamber, crawlspace, excavation or unstable wet area to investigate. Move property or take photographs only after hazards and active flow are controlled. If a meter, valve, equipment connection or affected area is unsafe or shared, stay clear and call from a safe location.

What Affects the Cost

The assessment scope depends on the system involved, floor construction, safe access, available isolation, number of possible sources, shared-building constraints and whether concealed areas or separate trades are involved. Pricing and deliverables should follow the confirmed scope rather than a universal instrument package, report or guaranteed result.

If You Live in a Strata, Duplex, or Rental Suite

A concern beneath a ground-floor strata unit or shared slab may involve unit-side or shared systems, common property and building-controlled access. Confirm the users served, shutoff control, property-management procedure and who can authorize testing or access. The assessment should not promise responsibility, authorization or coverage outcomes.

What to Have Ready Before We Arrive

• Any safely observed meter or usage change. Do not operate water-heater isolation, force a valve, use a municipal curb stop or enter a wet or restricted meter area.
• Where warmth, dampness, sound or finish changes have appeared, when they began and whether they change.
• Whether radiant heating, in-slab ducts or nearby equipment could affect temperature or sound.
• The floor and building construction type, renovation history and any available plans, if known.
• Whether the property is detached, shared, rental or strata-managed, and who controls access or shared shutoffs.