City lines constructed in the early 1930s through the 1970s featured asbestos cement pipes as their primary water and sewage transport systems. While these lines were initially thought to be durable and corrosion proof, they have since begun to degrade, releasing the asbestos fibers into the water supply. In some cases, the asbestos fibers form large enough clumps that they block plumbing and contaminate washing machines.

What is Asbestos-Cement Pipe

Asbestos cement pipes, also known as transite, are cement lines mixed with asbestos. At the time of their popularity, it was believed these pipelines were resistant to corrosion, making them more durable than standard cement or cast iron.

Transite gained popularity in the later 1930s to early 1940s. Many municipalities used asbestos cement pipe as their primary lines when laying new pipelines for water, sewer or storm drains. At the time, it was chosen for its lightweight design. The low friction coefficient made it perfect for liquid transportation. By the time workers ceased using asbestos lines, over 600,000 miles of it were used.

However, studies conducted in the early 1970s indicated the manufacturing of these lines were responsible for a growing number of health concerns. As such, the United States EPA issued a ban on asbestos products in 1979. While the original ban was defeated on appeal, the EPA heavily regulates its use. Manufacturers stopped mass producing asbestos plumbing in the early 1980s.

What Are the Health Risks of Asbestos Pipes

While asbestos is a naturally occurring fiber, it is linked to many health issues. The most common illness associated with asbestos is mesothelioma.

The average homeowner does not have to worry about developing this cancer using asbestos permeated pipes. However, it is a genuine concern for workers tasked with repairing and replacing these infested lines as the fibers may become airborne. Once airborne, the workers may inhale them leading to the development of mesothelioma. (See "Asbestos Cement Pipe: Why It's a Problem and How Trenchless Can Fix It.")

Homeowners do have to worry about the health risks associated with ingestion instead of inhalation. When an asbestos impregnated pipe begins to deteriorate, the fibers get into the water supply. Ingesting the fibers can lead to peritoneal mesothelioma, cancer similar to traditional mesothelioma which is caused by inhaling the fibers.

How to Tell There is Asbestos Line Pipes in the Home

Newly built homes do not have asbestos lined pipes. However, older homes built before the 1970’s are at risk. When purchasing the property, buyers should have an inspection which includes checking the existing plumbing for asbestos.

If the home was built before 1989, there is a chance that it may have asbestos somewhere in it. Documentation on the building may indicate whether or not pipes used in the structure are asbestos lined. However, construction files may be difficult to obtain depending on the age and some of the plumbing may have already been replaced many times over in the case of houses that are around 100-years-old or more.

A key indicator that pipes may have asbestos lining is in the insulation of pipes, or better yet the lack of insulation. Older pipes may no longer have the insulation wrapping still covering the entire line. Instead, there may be grey or white remnants of wrapping, especially around the fittings.

When inspecting the water and sewage lines, look for damage to the pipe. Damaged asbestos pipes allow the surveyor to see the asbestos fibers within the cement. If the pipeline is cracked, the asbestos may seep into the water flow causing contamination.

If you suspect the property has asbestos pipes, it is important you hire a certified professional to pull and obtain a sample. As asbestos is most harmful once it is airborne, taking a proper sample is risky and poses hazards to those who are not experienced in collecting procedures. There are home sampling kits with how-to instructions on obtaining a specimen. However, these should be used with extreme caution and pipe, or any other, samples should never be broken off to send for testing. Only collect pieces already detached to ensure safe collection.

Testing helps to identify not only if pipes have asbestos, but if the fibers are contaminating the water supply. The EPA allows for a contamination level of 7 million fibers per liter. However, it is recommended that any home with a potential asbestos contamination use a filtration system on their water lines.

How Can Trenchless Technology Fix Asbestos Pipe Issues

Despite the initial determination, asbestos cement pipes do break down. This deterioration may be caused by age, plant life, or settling of the ground around the lines. As such, municipalities now face the challenges of replacing the lines while protecting the safety of their people and the residents around the affected area. Trenchless technology plays a part in helping to prevent continued asbestos infiltration while repairing the service lines.

Cured-In-Place-Pipe

Cured-in-place pipe is a resin permeated liner that is pulled through the existing line. The technique allows the original asbestos cement pipe to remain in place while creating a new pipeline within the old one. The new line blocks the degrading asbestos filaments from entering the system, while the original pipe acts as a barrier to outside contaminants.

Sliplining and fold-and-form lining may be considered. However, the latter two lining options may prove problematic as grouting the annular space is awkward with the smooth interior of the asbestos pipe.

Pipe Bursting

A common choice for many municipalities is pipe bursting. With this process, a bursting tool breaks up the existing line and pushes it into the surrounding soil in a process known as fragmentation.

When breaking up transite lines, there are additional regulations, as breaking up more than 260-linear-feet can create a hazardous waste site. City officials need to check with local laws to ensure proper disposal.

Reaming

Like pipe bursting, reaming also breaks up the existing line. However, instead of leaving the small particles in the surrounding soil, this earth is often removed to create a place for the new line to go through. As with bursting, reaming more than 260-linear-feet of asbestos cement pipeline may face burdensome regulation.

Homes built during the 30s, 40s, 50s, and 60s, probably have at least one asbestos cement pipeline connected to it, unless owners rehabilitate the lines. The first sign homeowners see indicating asbestos contamination is once the pipe breaks and the fibers infiltrate washing machines, dishwashers, or showers. While there are health concerns, trenchless rehabilitation of the water and sewer lines can help lower risks.