Q&A: Municipal Water Treatment

  • Open How do I know plastic plumbing products are safe for use?

    Most state drinking water regulations and local plumbing codes require PE and PEX tubing and fittings conveying drinking water to meet NSF/ANSI Standard 61 to ensure components will not contribute harmful levels of contaminants to drinking water. All U.S. model plumbing codes and 46 of the 50 U.S. states require PVC drinking water system components to meet the requirements of NSF/ANSI Standard 61.

  • Open What is NSF/ANSI Standard 61?

    NSF/ANSI Standard 61: Drinking Water System Components-Health Effects is the American National Standard for health effects of drinking water system components. It establishes the health effects requirements for the chemical contaminants and impurities that are indirectly imparted to drinking water from products, components and materials used in drinking water systems.

    NSF/ANSI Standard 61 is overseen by the NSF Drinking Water Additives Joint Committee comprised of representation from the regulatory community, the manufacturing industry and user groups. The American National Standards Institute accredits NSF standards development procedures to ensure a balanced committee of stakeholders develops the standards in an open process. The NSF Council of Public Health Consultants, a group of 30 representatives from academia and local, state and federal regulatory agencies, provides technical advice on and oversight of the NSF standards.

    The NSF Health Advisory Board is a standing task group that consists of toxicologists from the U.S. EPA, Health Canada, state and provincial agencies, industry and private consulting firms. This group is responsible for reviewing and approving all allowable contaminant concentrations that are published in NSF/ANSI Standard 61.

  • Open How are plastic pipe, fittings and system components tested?

    First, we perform a formulation review of the material to determine what possible contaminants could leach out into drinking water and what type of chemical extraction testing is necessary. Our policy does not allow lead as an ingredient within plastic pipe formulations.

    We expose products to formulated exposure waters, and then analyze these exposure waters for contaminants. We use three separate formulated waters during product exposure: pH 5.0 and pH 10.0 (with 2 mg/L available chlorine for PE pipe and fittings) for extraction of metallic contaminants, and pH 8.0 for organic-based contaminants.

    PE products are tested at an ambient temperature of 73° F (23° C). PEX tubing samples containing water are heated to 140° F (60° C) for domestic hot water systems or 180° F (82° C) for commercial hot systems.

    Products are conditioned by exposure to the formulated waters (with the addition of 2 mg/L available chlorine for PE products) for 14 days, with water being changed on 10 of those days.  We then analyze the water collected from the final 16-hour exposure period for contaminants.  Any contaminants found must be below EPA or Health Canada levels for regulated contaminants.  For non-regulated contaminants found, NSF/ANSI Standard 61 sets health based pass/fail levels based on review of available toxicity data using the risk assessment procedures in annex A of the standard.

  • Open What types of analyses are performed on PEX tubing?

    Water exposed to PEX tubing and associated fitting systems is tested for the following contaminants as required by NSF/ANSI Standard 61:

    • VOCs (Volatile organic compounds)
    • Semi-volatile compounds (base neutral acid scan by gas chromatography/mass spectroscopy)
    • Phenolics
    • Regulated metals including antimony, arsenic, barium, beryllium, cadmium, chromium, copper, lead, mercury, selenium and thallium
    • Methanol
    • Tertiary butyl alcohol
    • MTBE (methyl tertiary butyl ether)
    • Any other potential contaminant identified during the formulation review

    These test methods are capable of detecting contaminants in water as low as 4 parts per billion (4 ppb) and lower, equivalent to a 0.0000004 percent concentration.

  • Open What types of analyses are performed on PE pipe and fittings?

    Water exposed to PE pipe or fittings is tested for the following contaminants as required by NSF/ANSI 61:

    • Volatile organic compounds (VOCs)
    • Semi-volatile compounds (base/neutral/acid target and scan by GC/MS)
    • Regulated metals including antimony, arsenic, barium, beryllium, cadmium, chromium, copper, lead, mercury, selenium and thallium
    • Any other potential contaminant identified during the formulation review
  • Open What types of analyses are performed on PVC products?

    Water exposed to PVC products is tested for volatile organic compounds (VOCs), phenolics, residual chloride monomer (RVCM), antimony, arsenic, barium, beryllium, cadmium, chromium, copper, lead, mercury, selenium, tin, thallium, phthalates (for flexible PVCs) and any other potential contaminant identified during the formulation review.

  • Open How do I know if plastic plumbing products meet this requirement?

    Plastic pipe, fittings and system components meeting the health effects requirements of NSF/ANSI Standard 61 bear either the NSF-61 mark or the NSF-pw (potable water) mark on the print string.  The NSF-pw mark indicates the product meets the health requirements of NSF/ANSI 61 as well as the performance, long-term strength and quality control requirements of NSF/ANSI Standard 14: Plastic Piping Components and Related Materials.

    If a PEX product has only an NSF-rfh mark, this indicates the product has only been evaluated for radiant floor heating applications.

    If a PVC product has only an NSF-dwv or NSF-sewer mark, the product has only been evaluated for drain, waste and vent applications or for sewer applications, respectively.

  • Open Where can I find NSF listed products?

    NSF certified products can be found in our online listings.

  • Open What ensures the product consistently meets these requirements?

    For products listed for potable water applications, NSF performs at least two unannounced audits of each production facility annually. During the audit, we verify the quality control tests being done by the manufacturer and that there are no modifications to the product formulation and processing. In addition, we collect samples for laboratory retesting of each product family on an annual basis.

  • Open Whom can I contact for questions?

    If you have questions about the testing and certification of any NSF certified product, contact our Consumer Affairs Hotline at 800.673.8010 or our Regulatory Affairs Hotline at 877.867.3435, or email info@nsf.org.

  • Open Who is NSF?

    Founded in 1944, NSF International is committed to protecting and improving human health and the environment on a global scale. NSF International is a global independent organization that provides standards development, product certification, testing, auditing, education and risk management for public health and the environment. Manufacturers, regulators and consumers alike look to NSF International for the development of public health standards and certification that help protect the world’s food, water, health and consumer products.

    In 1990, the U.S. EPA replaced its own drinking water product advisory program with NSF standards, including NSF/ANSI 61, for all materials and products that treat or come in contact with drinking water. Today, most plumbing codes require certification to NSF standards for pipes and plumbing components in commercial and residential buildings.

  • Open What’s the difference between NSF/ANSI Standards 372 and 61?

    NSF/ANSI 372: Drinking Water System Components — Lead Content contains the procedures to verify the lead content of drinking water products. This standard is referenced in Annex G of NSF/ANSI 61 as the methodology to determine lead content compliance. Products certified to NSF/ANSI 372 demonstrate compliance with lead content requirements only, while certifications to NSF/ANSI 61 Annex G demonstrate compliance with both lead content and lead leaching requirements.

  • Open Does NSF/ANSI Standard 61 only test for lead?

    No, NSF tests for other metallic contaminants as well as nonmetallic contaminants. In fact, the standard requires a full formulation disclosure of all chemical ingredients in each water contact material. The standard then requires testing for any chemical contaminant that might possibly leach from each material into drinking water.

  • Open Can a pure lead device pass NSF/ANSI Standard 61?

    No. This misconception started when an article reported that a small lead device was tested to the NSF/ANSI Standard 61 test protocol and it passed for lead. A close reading of the article shows that the lead device was only tested with pH 5 test water. It was not tested with pH 10 test water, which is required by the standard. The same article claims that other devices were tested with both pH 5 and pH 10 test waters and showed that the pH 10 test water was 71 times more aggressive for lead leaching than the pH 5 test water. If the factor of 71 was applied to the pH 5 test results for the small lead device, it would have clearly failed to meet the standard. In fact, many brass products containing only small amounts of lead have difficulty meeting the testing requirements of NSF/ANSI Standard 61.

  • Open How can I be sure that a faucet or plumbing device meets the NSF standard?

    Products certified to the NSF standard carry an NSF certification mark or a certification mark of the certifying organization. NSF International also maintains online listings of certified products and systems.

  • Open Which parties helped develop the NSF standard?

    The standard was developed using a voluntary consensus process. All interested parties were represented, including regulatory agencies, industry, water suppliers, consultants and other users of products covered by the standard.

  • Open Is NSF the only organization that can test against the standard?

    Any organization that is accredited by the American National Standards Institute (ANSI) to certify products to NSF/ANSI Standard 61 can test products against the NSF standard. Most states have regulations requiring products to meet NSF/ANSI 61 and all of these states require products to be certified by an ANSI-accredited certifier.

  • Open What are the requirements for NSF/ANSI 61 and lead?

    NSF/ANSI 61 contains requirements that restrict both the level of lead that can be contained in the water contact materials of drinking water products and the level of lead that can leach out. For more details about the requirements please download the NSF 61, NSF 372 and Lead Content brochure.