Hidden Leak Detected Under Kitchen Sink Using Flow & Dye Testing

Undetected plumbing leaks can quietly cause damage over time—often without obvious signs until the issue becomes serious. In this case, we identified a concealed leak that had been occurring for nearly a year beneath a kitchen sink.

The Problem

The client reported an unusual issue:
• Every time the sink was filled and then drained, water would surcharge (bubble up and overflow) from a concealed opening around the drainage pipe.

• The leak was not visible externally, making it difficult to pinpoint the exact source.
This type of issue typically indicates a hidden defect in the drainage system—such as a cracked pipe, failed joint, or blockage causing back pressure.

Our Approach

To accurately diagnose the problem, we carried out a flow and dye test, combined with a drain inspection camera (borescope).

1. Flow & Dye Testing

We filled the sink and introduced a coloured dye into the water. This helps track the movement of water through the pipe system and clearly reveals any escape points.
• As the sink was released, the dyed water made it easy to identify where the leakage was occurring.
• The test confirmed that water was escaping from a concealed section near the pipe entry point.

2. CCTV / Borescope Inspection

Using a high-resolution inspection camera:
• We inserted the scope into the drainage line.
• This allowed us to visually inspect the internal condition of the pipe.
• The footage confirmed a fault within the concealed pipe section, likely causing the backflow and surcharge.

What We Found

• A hidden defect in the drainage pipe (possibly a crack or joint failure)
• Water escaping into the cabinet cavity instead of flowing correctly through the system
• Pressure build-up when the sink was drained, leading to visible surcharging

Why This Matters

Leaks like this can go unnoticed for long periods and may lead to:
• Water damage to cabinetry and flooring
• Mould growth
• Structural deterioration
• Increased water bills

Early detection using the right tools can prevent costly repairs down the track.

Our Recommendation

Based on our findings, we recommended:

• Opening the affected concealed area for direct access
• Repairing or replacing the damaged pipe section
• Re-testing the system to ensure proper flow and no further leaks

Need Help with a Hidden Leak?

At Evolution Plumbing, we use advanced diagnostic tools like dye testing and CCTV inspections to accurately locate hidden plumbing issues—without unnecessary guesswork.
If you’re experiencing unusual drainage issues or suspect a hidden leak, get in touch with our team today.

Categorised in: News

This post was written by Andrew S