Descaling Cast Iron Pipes


Over time, cast-iron drain pipes can rust, causing flaky residues to build up inside the drain flow space. This deterioration can significantly increase the likelihood of drain clogs, which can cause inconvenience and potentially costly repairs.


Did you know that descaling can help rehabilitate old cast-iron pipes by restoring their inner surface? This procedure can effectively remove buildup and improve drainage, ensuring that your plumbing system functions optimally.


It may interest you to know that cast-iron pipes, commonly utilized for drainage purposes, may exhibit indications of requiring descaling after consistent use over a period of 35-50 years. Nevertheless, there is a solution to restore old cast-iron pipes through a comprehensive descaling procedure, which can potentially extend their lifespan by another 35-50 years, assuming no structural damages exist. Descaling is an effective method to prolong the life of drain pipes and can prevent homeowners from incurring costly drain replacements.

Process & Details

Over time, cast-iron pipes can accumulate rusty flakes scales which can cause blockage and other plumbing issues. To address this problem, a process called descaling is used. Descaling involves using a special tool called a descaling cable with attached descaling chain links. The chain links are tightly rigged and hold steel nail scrapers on each link. When the tool is activated, the chains spin at high speed and create friction in a filing motion that scrapes off the rust from the inside of the pipes. The rust debris is then flushed down the line with a constant high-pressure stream of water, ensuring that the pipes are cleared of any blockages and function properly.

By filing back the inner rusty scales and flushing the debris down the drain, the descaling procedure opens up the pipe for better flow. After the removal of the scales, the old cast-iron pipe resembles a new one in its look, flow, and functionality. Descaled cast-iron pipes function better as those flaky obstructions that trap deposits every time a toilet is flushed are eliminated and the propensity of drains clogging are minimized.

The descaling process typically starts at the end of the drain system and continues upward toward the opening. Descaling can be a tedious process of filing the clog-creating obstructions, hydro-jetting the loose scales, and video inspecting to ensure quality work. Descaling takes patience and care and if performed correctly should be time consuming.


The descaling machine is composed of a cable inside a vinyl sleeve with an attached chain link head. The cable turns in high revolutions inside the sleeve and is constantly lubricated by the water pressure running inside. The machine has a high torque capability and its speed can be varied depending on the job.

Curry and Son’s inspect drains daily during service calls to ensure the best recommendations are made to our clients for their unique drain systems and issues.

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