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If you are looking for an expert witness on PEX plumbing systems piping, then click here.
Quick Question about PEX Tubing Safety for Drinking Water
Here is a quick question that came from a home owner.
PEX sites seem to not mention whether any particular Color of PEX has drinking water issues. In particular, Red PEX is nominally used for hot water and you wouldn't typically drink hot water. Is there anything wrong with using Red PEX (versus Blue PEX) for drinking water services? For example, what if the installer had some leftover Red PEX and just joined it into the Blue PEX line to provide drinking water service permanently. Anything drinking water concerns with this practice?
PEX sites seem to not mention whether any particular Color of PEX has drinking water issues. In particular, Red PEX is nominally used for hot water and you wouldn't typically drink hot water. Is there anything wrong with using Red PEX (versus Blue PEX) for drinking water services? For example, what if the installer had some leftover Red PEX and just joined it into the Blue PEX line to provide drinking water service permanently. Anything drinking water concerns with this practice?
Answer
Any piece of PEX tubing 5 feet long or longer contains a complete print line which will be helpful in resolving your concerns.
If the red tubing print line documents compliance with NSF-61, then it is certified for use in drinking water applications. Red PEX is color-coded for the convenience of the installer to identify it as a hot-water tubing, but PEX of all colors which is intended for plumbing must carry the same certifications. If the red tubing print line does not document compliance with NSF-61, then is it not certified for use in drinking water applications.
The appearance of the marking “NSF pw” or “NSF-61” in the print line tells the end user the certification status of the tubing for drinking water use.
This NSF publication in the following link provides good clarity on these certifications. Link to Page.
Keep in mind that some red PEX tubing is intended for hydronic heating applications and has an oxygen diffusion barrier coating. In that situation, the tubing may or may not be certified for drinking water in accordance with NSF 61.
In the end, the simple answer is that inspection of the print line on the tubing is the best way to answer the question for your specific installation rather than relying on any generalities.
For more information on topics related to PEX drinking water safety, please read the article below.
PEX Pipe Is Safe For Drinking Water. Here's Why
Many people question the safety of PEX pipe and tubing for drinking water. PEX pipe is safe for drinking water in households and commercial systems. NSF International has teams of toxologists and other technical professionals who administer the NSF 61 standard which requires all components in a water system to be safe for drinking water. This includes PEX pipe systems with drinking water. The NSF's "mission is to protect and improve global human health. As an independent, accredited organization, NSF will "test, audit and certify products and systems as well as provide education and risk management." Manufacturers, regulators and consumers look to NSF to develop public health standards and certifications that help protect drinking water.
Concerns about drinking water safety from a PEX system are sometimes raised shortly after a brand new PEX water system is installed and an unpleasant odor and taste is reported. This usually occurs in only brand new systems and will dissipate with use as fresh water replenishes the system. Often the concerns about the odor or taste of the water coming from PEX water systems merely note that the water is "different" than water from a water system made from another material. The public should be mindful that not everything that is "different" is "dangerous" and the truth remains that trained health professionals are firmly in control of the regulation of the materials used in the supply of drinking water. Of course, all potable water pipe system components which contact the water are individually regulated and required to meet high standards in order to guarantee the safety of drinking water.
In addition to compliance with NSF 61, all PEX tubing must meet other rigorous industry standards including demonstration of their durability under the chlorine disinfection conditions used for potable water. PeX tubing is tested to demonstrate acceptable durability while in contact with chlorinated water by ASTM F2023. Every material has its limits and manufacturers commonly provide guidance on the maximum use temperature of their PEX products in hot chlorinated water. According to the Plastic Pipe Institute, PEX is generally not used for water temperatures above "140°F OR system pressures above 80psig or highly aggressive water quality OR any combination thereof can significantly reduce the service life of the tubing.” Operating a PEX potable water system at extremes of temperature or pressure may reduce the lifespan of the pipe to 10 years or less. However, as long as temperatures and pressures are operating under the correct conditions, PEX is both highly durable and safe for drinking water due in part to testing to demonstrate compliance to ASTM F2023 and NSF 61.
You can read more about PEX pipe safety and drinking water regulations here.
You can also read our PEX pipe size page here.
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