Is Plastic Piping Safe?

Pros and Cons of Plastic Drinking Water Pipes

The pipes that carry your tap water come in a variety of materials–from lead to copper to plastic. With lead piping now illegal and copper piping very expensive, that brings us to one of the most popular plumbing materials today: plastic. 

There are a variety of different types of plastic piping—from PVC to CPVC to PEX. In this newest Tips For Taps piece, we ask and answer the following questions:

• Why has the United States transitioned to plastic piping?
• What are the differences between various plastic piping options?
• What are the exposure risks of various types of plastic piping? 
• What are the benefits of plastic pipes?
• What are the potential dangers in plastic pipes?
  

The State of US Drinking Water Infrastructure

To put it bluntly–U.S. drinking water infrastructure is in poor form.

Much of the current drinking water infrastructure in the United States is deteriorating and (over)due for an upgrade. In the next decade, it is estimated that the U.S. government will need to spend an estimated $300 billion on municipal water infrastructure. The question at hand is: what will that new infrastructure consist of? 

There is an ongoing debate as to what material should be used for new pipes, mains, and fixtures. With such  large-scale projects nationwide, it is imperative that we question the safety, sustainability, and durability of the pipes under review for use in new projects. .

Some of the pipes still in use today are up to 150 years old and their deterioration contributes to health risks and resultantly poise their own potential health consequences. Substantial scientific evidence indicates that over an extended period of time, old pipe materials like lead and iron, are associated with serious health impacts including lead poisoning, Legionnaire's Disease, cancer, heart disease and Alzheimer’s disease. 

Many of these metals have been phased-out as a supply for new water infrastructure due to cost and serious associated and unforeseen human health impacts. 

Today, plastic pipes are widely replacing metal ones. While no long-term data exist on exposure to plastic in drinking water, the studies we do have on plastic exposures through drinking water suggest there are indeed potential adverse health impacts.

In this article, we’re going to walk you through the history of pipes and how the plastic revolution may solve some problems, while at the same time, create new ones.

Why Plastic Pipes and What Types?

During World War II, the expansion of plastic production was argued by industry and politicians as a necessity. This was likely compounded by the fact that plastic is a petroleum byproduct and fossil fuel interests have long influenced U.S. government. Many of the natural resources and metals were needed for war efforts. Plastic became an increasingly popular building product and the material of choice for a majority of U.S. water supply pipes. Since the 1950’s, a variety of different plastic pipes have been created and used.

The most popular and widely used plastic pipes for water are:

• Polyvinyl chloride (PVC)
• High-density polyethylene (HDPE)
• Cross-linked polyethylene (PEX)
• Chlorinated polyvinyl chloride (CPVC)
  

Plastic Pipes and Potential Health Risks

While plastic piping is certainly cheaper than many alternatives on the market, not enough is known about their potential health hazards to confidently argue that plastic should be the material-of-choice as the U.S. upgrades it’s drinking water infrastructure. 

An increasing number of studies suggest that some plastic pipes leach harmful chemicals, as well as accumulate heavy metals such as lead. Additionally, certain contaminants from polymeric pipes may contaminate the water. This may occur by diffusion of chemical components from the pipe itself or by decomposition of chemicals used during the pipe production.

For an overview of potential health risks associated with various plastic pipes, read on:

Polyvinyl Chloride (PVC)

• PVC contains DEHP (a phthalate) which can disrupt hormones (i.e an endocrine disruptor) and may lead to potential reproductive effects such as feminization, reduced fertility in males, decrease in the birth of female offspring.

High-density Polyethylene (HDPE)

• To date, there is no conclusive evidence to suggest HDPE leaches hormone-disrupting chemicals or carcinogenic substances into water. 

Cross-linked Polyethylene (PEX)

• Though many water pipes are underground, PEX pipes are susceptible to degradation by UV rays and if exposed to sunlight, the molecular structure disintegrates. This causes the piping to become brittle, rupture, and leach plastic compounds into water. 
• Note: there are different types of PEX piping, namely PEX-a, PEX-b, and PEX-c. Of the three, PEX-a is considered the most preferable due to the fact that is the most flexible with no weak links in the molecular chain. (Read about the manufacturing process).
  

Plastic Pipes: An Overview 

What are the benefits of plastic piping?

• Plastic pipes are lightweight and easy to install.
• 50 percent cheaper than iron, plastic pipes are typically the least expensive piping option on the market.
• Plastic pipes can easily be replaced and repaired.
• Plastic pipe production emits less carbon dioxide than metal pipe production. 
  

What are the dangers of plastic piping?

• There is limited scientific research on the effects of plastic on the quality and safety of drinking water.
• Research into plastic pipes in water has identified at least 158 contaminants as potential leachates.
• Toxic pollutants such as benzene and toluene can permeate certain types of plastic pipes as they age.
• Plastic is a non-renewable resource and is often difficult to recycle.

Concerned About Your Plastic Pipes? 

Because water treatment (like chlorine and chloramines) and pipe-brand impact the final tap water quality, we can’t make a blanket statement about the health impacts of plastic pipes. That said, research continues to emerge. 

Researchers have found 158 compounds in drinking water associated with plastic pipes, and a recent study on PEX discovered highly variable impacts on tap water quality, taste, and smell. 

Testing your water for plastic chemicals that may be leaching into your water is the best way you can protect yourself.

Tap Score's SVOC Water Test will analyze for a broad range of plastic-related, semi-volatile organic compounds from a wide array of potential sources.  Additionally, the Advanced City Water Test and Advanced Well Water Test both include analysis for volatile compounds associated with plastic pipe leaching. The Extended Well Water Test is a great way to cover SVOCs and VOCs. 

Each of these in-laboratory water tests will provide quantified results–along with a health-risk analysis. We will help you interpret your results, as well as provide unbiased, treatment recommendations based upon your water’s unique chemistry.

More questions? Tips for Taps is a great resource for an array of water quality related issues. Still curious? Our team of scientists is always available by chat or email. Contact us anytime at hello@gosimplelab.com. We’re always standing by!