How to locate a blocked drain with a CCTV drain camera

🔧 How to locate a blocked drain with a CCTV drain camera

Plumbing work in Australia must be performed by a licensed plumber. This guide explains the process and helps you select the right tools and materials.

What is the standard process for locating a blocked drain with a CCTV camera in Australia?

Using a CCTV drain camera is the standard professional method for accurately locating blockages, offsets, root intrusion, collapsed sections and grading defects in sanitary drainage and stormwater lines. For Australian trade professionals, the process should be carried out in line with the PCA and AS/NZS 3500 requirements, with findings confirmed by sonde locating, depth readings and clear defect reporting for repair planning.

What skill level is required for CCTV drain camera operation in Australia?

Advanced — Estimated time: 1–3 hours depending on access, drain condition and line length

What specific tools are required for CCTV drain inspection and blockage location?

What materials are needed for a professional CCTV drain inspection?

Safety Requirements

Step-by-Step Guide

Step 1: Assess the job history and identify the likely drain section

Start by confirming the nature of the blockage: recurring fixture overflow, gully surcharge, slow discharge, rain-related backup, or isolated branch line restriction.

Check previous service notes if available. Repeated blockages in the same section often indicate tree root intrusion, a belly, joint displacement, scale build-up or a partial collapse rather than a simple soft obstruction.

Identify whether you are inspecting:

💡 Knowing the pipe material in advance—PVC-U, earthenware, cast iron, HDPE or concrete—helps interpret the footage and likely failure mode.

Step 2: Select the best access point

Choose the most direct and serviceable access into the line. Preferred entry points include:

Aim to inspect in the direction that gives the clearest diagnosis. In many jobs, this means entering from downstream and pushing upstream so the camera faces into the obstruction and defect zone.

Where the line is fully blocked and water level prevents visibility, open and clear the line first using a jetter or drain machine as required.

Step 3: Pre-clean the drain if visibility is poor

A camera is a diagnostic tool, not a cutting tool. If the line is holding silt, grease, wipes, paper mass or root mat, perform a preliminary clean so the inspection provides usable footage.

Use:

Do not over-clean before recording if the purpose is to document the cause of recurring failure. Capture enough initial evidence of the blockage condition, then clean and reinspect to assess pipe integrity.

💡 On insurance or real estate reports, record “before” and “after” footage wherever possible.

Step 4: Set up and calibrate the CCTV camera system

Inspect the camera head, lens, lights, skids and push rod for damage before insertion. Confirm the sonde is transmitting and the metre counter is zeroed or noted.

Set the correct skid size for the pipe diameter:

A correctly sized skid helps keep the camera centred, improves image quality and provides more reliable sonde locating.

Check:

Step 5: Insert the camera and begin the inspection run

Feed the camera steadily into the drain without forcing bends or junctions. Maintain slow, controlled advancement to avoid passing defects too quickly.

Watch for:

In sanitary drains, note water level carefully. A small trailing flow is normal; persistent standing water may indicate grade issues or a downstream restriction.

Pause at each defect and record:

Step 6: Locate the exact position of the blockage or defect from above ground

Once the camera head reaches the obstruction or identified defect, stop pushing and activate or confirm the sonde signal.

Using the locator receiver, sweep the area above ground to identify:

Mark the surface with paint, chalk or flags. Record:

For higher accuracy, cross-check the sonde location from two directions. This is particularly important in reinforced slabs, near metal fencing, or where multiple buried services may distort readings.

💡 Always distinguish between metre count along the pipe and direct above-ground offset distance. They are not the same in bends or changes of direction.

Step 7: Confirm the extent of the defect by advancing and retracting

Do not rely on a single pass. Advance slightly beyond the defect where possible, then pull back slowly to confirm:

For root intrusion, determine if it is:

For collapsed drains, confirm whether the line is fully impassable or if there is enough remaining bore to permit temporary restoration.

Step 8: Inspect all connected sections if the blockage is recurring

Recurring blockages often involve more than one defect. Continue to inspect:

Common examples include:

A complete diagnosis supports the correct repair recommendation and helps avoid repeat call-backs.

Step 9: Record evidence and classify the defect clearly

Capture stills and video of each finding with clear verbal or written annotations. Use consistent terminology suitable for trade and client reporting.

Include:

Typical recommendations may include:

Step 10: Verify the repair strategy before excavation or rectification

Once the blockage location is identified, confirm whether the issue is serviceable by cleaning, no-dig repair or excavation.

Assess:

If excavation is planned, mark the proposed dig zone conservatively and arrange service locating if there is any uncertainty.

Step 11: Complete the report and communicate findings

Finalise the inspection with a clear trade report. Include:

This is particularly important for insurance, strata, body corporate, builders, property managers and pre-purchase drainage reports.

Common Mistakes to Avoid

Pro Tips

Recommended Tools

⚠️ Safety

🔒 Licensing

Plumbing and drainage work must be carried out by a licensed plumber in Australia. Licensing requirements vary by state and territory, including NSW Fair Trading, VIC VBA, QLD QBCC, and WA Building Commission. Gas work requires a separate gas fitter licence.

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