Check plans first, inspect through safe existing access, then scan the floor with a suitable pipe-and-cable detector. Thermal imaging may help indicate an active hot-water line. These checks identify probable routes only; visually confirm the pipe or arrange professional location before drilling, screwing, cutting or lifting flooring.
Understanding where pipes commonly run through walls or floors provides useful context, but no typical route proves that a specific area is clear.
Checks and tools
Review available plans: Check building plans, renovation drawings and as-built records. Routes may be approximate, and later alterations may not be documented. Compare plans with fixtures and floor wastes, but do not assume pipes run in straight lines.
Inspect from below where safe: Through existing underfloor access, use a torch to look for pipes, branches and penetrations through joists or flooring. Do not enter a wet, cramped, poorly ventilated or otherwise unsafe subfloor space.
Scan the finished floor: Use a pipe-and-cable detector or multi-service scanner suited to the floor construction and suspected service. Follow its calibration and depth instructions, scan in both directions and mark consistent readings as a probable zone, not an exact centreline. Readings may also indicate cables, reinforcing mesh or metal fixings.
Use thermal imaging only as supporting evidence: With hot water flowing, a thermal camera may reveal a surface-temperature pattern above a hot-water pipe. Results depend on the pipe depth, insulation and floor material. Thermal imaging does not see through flooring and is generally unsuitable for locating cold pipes.
Why detection may be uncertain
Pipe material, depth and floor construction affect results. Compatible scanners usually detect conductive metal more readily than plastic. Plastic pipes may produce no direct reading unless they include a detectable tracer or cause a measurable temperature difference.
Tiles, underlay, thick flooring, foil insulation, reinforcing mesh, fasteners and nearby cables can mask pipes or produce ambiguous readings. Existing nails and screws may indicate joists or battens, but they do not prove that an area is clear of services.
If moisture, pressure loss or unusual water-meter movement suggests damage, locating an underground water-pipe leak requires a different investigation from mapping a route before drilling.
When professional confirmation is necessary
Do not penetrate or lift the floor based only on plans, fixture positions or one detector reading. Concealed areas may also contain electrical cables or gas services. Keep DIY checks non-invasive: review records, scan the surface and observe only through safe existing access.
Stop if the checks disagree, detection is obstructed, the route remains uncertain or suspected asbestos blocks access. Do not drill, lift or sample material that may contain asbestos, enter an unsafe subfloor space, or open plumbing to insert tracing equipment.
Before disturbing the floor, have the route confirmed visually by a licensed plumber or suitable service locator. If hidden moisture or a pipe fault is suspected, contact our concealed water leak detection team to assess the area and advise on the next step.