Old clay sewer pipe: what it is, how long it lasts and when it fails

Old clay sewer pipe is vitrified clay, a clay and shale mix fired in a kiln until it becomes a hard ceramic. The pipe itself resists almost everything that goes down a house drain, and it can last a very long time. What fails is the joints between the short lengths, where roots creep in and the soil shifts. If your house has a lateral that old, the question is rarely whether the clay is rotten. It is whether the joints are still tight. For other work on the line, see drain cleaning in Los Angeles.

What is vitrified clay pipe in a sewer?

Vitrified clay pipe is sewer pipe made from clay and shale that is shaped and then fired at around 2,000 degrees Fahrenheit until it turns into a glassy ceramic. The firing makes it dense and chemically inert. It was a common choice for house laterals and street mains for generations, and some of it is still in use.

Its good points are well known. It stands up to acid, including the sulfuric acid that forms in sewers, and it tolerates rougher cleaning than plastic. Its weak points are just as plain. It is heavy, brittle, and laid in small lengths, so there are many joints. Each joint is a place where a root can find a way in.

That is why a clay lateral can have a perfect pipe wall and still cause trouble. When we say "old clay pipe," we usually mean "old joints."

How long does old clay sewer pipe last?

Published figures run from about 50 years to 100 years or more. The low end reflects joint failure, and the high end reflects the clay itself. A line in steady, dry soil with no big trees can reach the top of that range. A line under a root-heavy lawn can need work much sooner.

There is no national number you can trust for your own line, and none of those figures were measured in Los Angeles. What decides it is:

• Joint type. Old mortar or tar joints do not flex. Later rubber-gasketed joints hold better.
• Roots. Roots enter at joints and swell, which opens them further.
• Ground movement. Clay cannot flex, so settling or shaking can crack a length or offset a joint.
• Cleaning history. Aggressive blades or a badly aimed water jet can chip a joint.

Your house's age is a clue, not a verdict. Clay was widely used in older homes, and sources describe it as common before about 1980, which is a reason to look, not a reason to panic. A camera tells you the truth.

How can I tell if my old clay sewer pipe is failing?

The warning signs are repeat backups, slow drains throughout the house, gurgling when you flush, and a sewer smell outdoors. Roots are the classic cause. If the same drain stops up within a few months of being cleared, the line likely has a defect that cleaning will not fix.

Use this as a quick check:

To be sure, a camera has to go down the line. A sewer camera inspection shows roots, offsets, cracks and any bellies, and gives you footage you can show an estimator. If you plan to buy a home with an old lateral, a sewer scope inspection is the version done before closing.

What are my options for an old clay sewer line?

You can keep it and maintain it, repair a single break, line it, or replace it. Keeping it works when the camera shows tight joints and little root growth. A spot repair fits one bad length. Lining and replacement suit a pipe with problems all along the run. Which one depends on what the camera finds.

The routes side by side:

• Maintain. Camera every few years, cut roots when they return, avoid harsh jetting.
• Spot repair. Dig down and swap a broken length. See repairing clay sewer pipe.
• Line it. A resin liner seals joints and cracks from inside. See sewer pipe lining.
• Replace it. Open trench, or pipe bursting that pulls new pipe through the old. See trenchless pipe replacement.

If you are unsure between lining and replacing, our lining versus replacement guide sets out how each fares on clay.

Does old pipe in Los Angeles have extra rules or risks?

The main rule is who owns it. Los Angeles County Public Works says the property owner is responsible for the entire lateral, including the part under the street. A failing clay lateral is therefore the owner's repair, and the owner pays.

Two more points matter here. Camera inspections done by a bonded sewer contractor can qualify for a city rebate, up to $300 on the program's current terms, so check the city's page before you book. And repairs in the public right of way go through a separate city permit.

Not every old pipe is clay. Between the 1860s and the 1970s some laterals were laid in Orangeburg, a pipe made of tar-soaked wood pulp that tends to go oval and collapse. It cannot be treated like clay, and a camera shows the difference.

Ask for a written price and a recording before agreeing to any of the above. You can send a quote request, and we arrange a visit from a local drain cleaner who explains what the camera found.

Questions people ask

Is clay sewer pipe bad?

No. The clay itself is durable and resists sewage chemistry. The problem is the number of joints, which let in roots, and its brittleness when soil moves. A clay line in good shape is fine to keep. A clay line with failing joints is worth lining or replacing.

Can old clay sewer pipe be cleaned?

Yes, and it usually is. Cables and blades cut roots, and water jetting washes out grease and debris. On old clay, jetting must be done carefully, because a stationary high pressure jet can chip joints. A camera before cleaning shows what pressure is safe.

Do I have to replace old clay sewer pipe?

Not necessarily. If the camera shows joints that are tight, no major cracks and a steady fall, many homeowners keep a clay lateral for years with periodic root cutting. Replace or line it when problems are widespread, when backups keep coming back, or when a section has collapsed.

How do I know if my sewer pipe is clay?

The camera shows it, and a plumber can often tell from a cleanout. Clay looks dull orange to gray-brown, in small lengths with a bell at each end. Cast iron is dark and rough, plastic is smooth. If you are not sure, ask for a camera look.

Is a cracked clay sewer pipe covered by insurance?

Most standard homeowner policies do not cover wear and tear or root damage to a lateral, though some offer optional line coverage. Read your policy or call your insurer. Our page on whether home insurance covers sewer line replacement goes through the usual terms.