Our Drain and Sewer Company, LLC uses flex shaft milling equipment to remove rust scale and mineral buildup from the inside of cast iron drain pipes. This service restores the original diameter of pipes that have narrowed over time due to corrosion. You might notice slow drains throughout the house, frequent backups, or standing water in sinks and tubs even after traditional snaking.

Cast iron pipes corrode from the inside, creating rough, uneven surfaces that catch debris and restrict water flow. Flex shaft milling uses a flexible rotating cable with abrasive cutting heads that remove scale layer by layer without damaging the underlying pipe. We select the cutting head size and grit based on pipe diameter and the thickness of buildup shown during the camera inspection.



If you own a home built before 1975 with cast iron drain lines and experience recurring slow drainage, contact us to schedule a camera inspection and discuss whether milling is appropriate for your system.

What Happens During Flex Shaft Milling

We start with a video inspection to measure the extent of scale buildup and confirm that the pipe structure can handle milling. The camera reveals the interior diameter, location of heavy buildup, and any sections with advanced corrosion or structural damage. You see the footage and receive a clear explanation of what the equipment will accomplish.

Our Drain and Sewer Company, LLC feeds the flex shaft cable through the line, rotating the cutting head at controlled speeds to remove scale without over-milling. After milling, we perform a second camera inspection to verify that the pipe interior is smooth and flow capacity has been restored. You will notice water draining faster and fewer instances of standing water in fixtures.



Milling does not repair cracks, offsets, or severely corroded sections. If the camera shows structural damage, we discuss whether spot repair or pipe lining is needed. We provide realistic expectations about how long restored flow will last based on the condition of your specific system.

Property managers and homeowners often ask how milling differs from snaking, whether it works on all pipe types, and what results to expect.

What is the difference between flex shaft milling and regular drain snaking?

Snaking clears blockages by breaking through clogs, while milling removes the buildup attached to pipe walls. Milling restores pipe diameter and improves long-term flow, especially in cast iron systems with heavy scale.

How do you know if my pipes need milling or just hydro jetting?

We use camera inspections to determine the best method. Milling is used for hardened scale that jetting cannot remove, while jetting works well for grease, debris, and lighter buildup after mechanical removal.

Will milling damage old cast iron pipes?

Milling is safe for structurally sound cast iron. We adjust rotational speed and select cutting heads based on pipe thickness and condition. If the camera shows advanced corrosion or thin walls, we recommend alternative solutions.

How long does the milling process take?

Most residential milling jobs take two to four hours depending on the length of the affected pipe and the severity of buildup. We provide a time estimate after inspecting the line.

Can flex shaft milling be used in Denver homes with older plumbing systems?

Yes, many Denver homes built in the mid-twentieth century have cast iron drain lines that benefit from milling. We assess each system individually and confirm that the pipe can handle the process before starting work.

If your drains are slow despite repeated snaking, or if you know your home has cast iron pipes and reduced flow, reach out to Our Drain and Sewer Company, LLC to schedule an inspection and determine whether flex shaft milling will restore performance in your system.