We offer Financing!

Click to Learn More

5 Causes of Main Drain Line Problems

The drain line is the pipe that connects all the drains in your house to the sewer system. A damaged main drain line can make your life miserable. Your shower, toilets, and sinks drain slowly or back up. Your yard may smell like wastewater. You may even develop a sinkhole. Here are five reasons you may need drain line repair:


Although galvanized steel piping can last 30 to 50 years when used in plumbing and potable water service, galvanized steel is not used for the drain line. Rather, a drain line is usually constructed from clay pipe, cast iron, or plastic.
Plastic and clay pipe are not prone to corrosion, although they can deteriorate for other reasons. Cast iron, on the other hand, corrodes.
Corrosion is a chemical process in which one material converts into another material due to electron exchange. Iron atoms in the presence of water will tend to donate electrons to oxygen molecules in the air. This creates oxygen ions and iron ions. Water molecules then react with the iron ions to form iron oxide or rust. Given enough time, water, and air, the cast iron pipe will crumble into iron oxide dust.
When a drain line is severely corroded, plumbing companies typically recommend drain line replacement. Drain line replacement involves a San Diego plumbing company digging a trench to reach the drain line and replacing the corroded drain line.

Pipe Erosion

Pipe erosion is a mechanical process that occurs on the inside and outside of the pipe as it wears down. This causes a thinning of the pipe walls and eventually leads to cracks and leaks.
Pipe erosion on the inside of a drain line occurs simply because moving water will wear the inside of a pipe. If there is debris or sediment, the wear will occur faster. Think of it this way: if you have two materials rubbing against each other, they will tend to wear down, but if you introduce grit, sand, or dirt between them, they will tend to wear down faster. This is exactly what happens inside of a pipe. Wear will occur even though one of the materials is a liquid and the other is a solid.
Pipe erosion will occur on the outside of a pipe too. The soil surrounding the drain pipe can wear down the outside of the pipe, especially when it is under pressure or vibrates. In a seismically active area like San Diego, this is not unheard of.
As the pipe erodes, leaks can develop. The wastewater leaking into your yard can leave the yard smelling bad and, over time, can erode the soil causing a smelly sinkhole to form. Drain line repair, such as lining the inside of a drain line, may fix these problems without necessitating a full-blown drain line replacement.

Soil Subsidence

Soil settles over time. Soil also erodes due to water flows. When the soil supporting a drain line subsides, a drain line can sag. Water flows through drain lines due to gravity rather than pressure. This means that a sagging drain line will back up. Moreover, wastewater can accumulate where the drain line sags, leading to corrosion.
Sagging drain lines will almost inevitably lead to drain line repair or replacement. Aside from the problems that sagging brings, drain lines are not intended to withstand the stresses associated with sagging. Sagging can eventually lead to cracking.


Drain lines can become clogged with material that goes down the drains, either deliberately or accidentally. One of the worst culprits is kitchen grease. Pouring kitchen grease down the drain leads to a condition similar to arteriosclerosis in which cholesterol clogs the body’s arteries. The kitchen grease cools off and solidifies inside the drain pipe, causing a blockage.
Drain line repair for a clogged drain line can be as simple as hydrojetting the pipe and inspecting it for damage.


Tree roots growing around a drain line can find cracks and seams in the drain line and eventually break it open. This can cause leaking and backing up. Repairing a drain line that has become compromised by tree roots can include hydrojetting to clear the roots and lining the inside of the drain line.
Drain line repair by a San Diego plumbing can correct drainage problems caused by corrosion, pipe erosion, subsidence, and blockages.

Skip to content