By: Irina Garbar / UL Project Engineer

When we talk about water, we talk about everything. Water, undeniably the most essential element, does more than just quenches our thirst – it helps our body remove wastes, aids in digestion, prevents dehydration, regulates our body temperature, protects organs and tissues and lubricates joints. The health authorities commonly recommend drinking at least eight 8 ounce glasses per day, which equals to about 2 liters. Indisputably, consuming the required amount of water is important to our health, but the quality of water should not be less important than the quantity.

When it comes to drinking water, is it always safe?

In 1974, Congress enacted the Safe Drinking Water Act (SDWA) intended to regulate the quality of drinking water. Under this law, the US EPA was given the authority to set national standards for drinking water to protect the public from exposure to naturally occurring and man-made contaminants. Nevertheless, the news of contaminated drinking water has dominated headlines for months now. There are a number of threats to drinking water, including the improper disposal of chemicals, fertilizer runoff, aging infrastructure, and water main breaks resulting in the SDWA not being met. According to one study conducted by the Natural Resources Defense Council (NRDC), in 2015 there were more than 80,000 reported violations of the SDWA, including exceedance of maximum acceptable levels of health-based contaminants.

The health-effects of drinking contaminated water could range from feeling unwell to severe illness, while some might not be noticed for many years. For example, according to the CDC, even low levels of lead in tap water can enter the bloodstream of children, and among other issues, result in slow growth, hearing and behavioral problems and anemia. Lead exposure in adults could cause a variety of health- issues, including fertility, cardiovascular and kidney effects. Short term exposure to Arsenic from tap water begins with headaches, confusion and drowsiness, leading to cancers and heart diseases in the long term.

Consumer water treatment systems, including water filters, are designed to address many health and non-health related contaminants, keeping your water safe and great testing. There are hundreds of brands of differently shaped and sized waters filters available in today’s marketplace, including pitchers/dispensers, faucet mounted/faucet integrated, refrigerator, under-the-counter/countertop and whole house filters. These products claim to reduce specific contaminants and keep the water safer.

With so many options on the market, how do manufacturers distinguish their product from the competition and give consumers confidence in its ability to reduce contaminants in a consistent and effective manner? How do they help ensure their filter is structurally sound and is not contributing contaminants into drinking water above the Maximum Contaminant Level (MCL) established by the EPA? How do they safeguard their reputation and reduce liability risks?

Luckily, UL offers independent testing and certification to voluntary industry standards for manufacturers of residential drinking water filters, including NSF/ANSI 42 – Aesthetic Effects and NSF/ANSI 53 – Health Effects. Both standards have identical requirements when it comes to evaluation for the material safety and structural integrity, but differ in the type of contaminant reduction testing performed.

NSF/ANSI 42 and NSF/ANSI 53 standards were developed on a consensus basis between manufacturers, public health and regulatory officials, consumer representatives, and independent ANSI-accredited third-party certifiers such as UL, IAPMO, NSF and WQA.

Material Safety and Structural Integrity of Residential Water Filters (NSF/ANSI 42 and NSF/ANSI 53)

Both standards contain mandatory testing requirements for the water filter’s wetted materials to ensure that they do not add harmful contaminants to the drinking water. The material evaluation consists of a three-step process:

  • Formulation review of all wetted materials to determine a test plan
  • Material extraction testing to the test plan
  • Review of analytical test results against pass/fail criteria in the standards

In addition to material safety, water filters connected to a pressurized water supply line are evaluated for structural performance to help ensure the design and fabrication quality of the product. The structural integrity (cyclic and hydrostatic pressure) test requirements vary depending on the type of water filters, but the outcome must remain the same: The product and its components must remain watertight through the test.

Performance of Residential Water Filters (NSF/ANSI 42 and NSF/ANSI 53)

Both NSF/ANSI 42 and NSF/ANSI 53 standards establish performance requirements for water filters designed to reduce specific contaminants from potable water.

Water filtration systems certified to NSF/ANSI 42 are intended to minimize aesthetic, non-health related contaminants from public or private water supplies, including chlorine (taste and odor), chloramine, hydrogen sulfide, phenol, iron, manganese, pH neutralization, zinc and particulate reduction.

Performance of household water filters designed to reduce contaminants that are considered harmful is evaluated under NSF/ANSI 53. Such contaminants include lead, arsenic, mercury, nitrates/nitrites, VOCs, cyst and many others that can be found in drinking water.

It is worth noting that in order to obtain a certification to either standard mentioned above, a water filtration system must make at least one contaminant reduction performance claim.

In addition to material safety, structural integrity and contaminant reduction testing requirements, NSF/ANSI 42 and NSF/ANSI 53 also sets criteria for literature that must accompany each system. This literature contains important information on the proper usage and limitations of the system and educates them on the performance of the product. Standard requirements apply to the following four pieces of literature:

  • Installation, operation, and maintenance instructions
  • Data plate (a permanent plate or label affixed to the system)
  • Performance data sheet
  • Replacement component literature (for each replacement element)

To ensure continued compliance, all certified water filters are required to go through a full re-evaluation and retesting program at least once every five years. In addition, during the five-year period, each manufacturing facility is subjected to at least one annual inspection. These inspections include an assessment of the certified product to help ensure it has not changed since the original evaluation, a review of the manufacturer’s quality assurance program, and an examination of the certified product’s literature.

It is apparent that certification of water filtration devices to NSF/ANSI 42 and NSF/ANSI 53 standards with an ANSI accredited third-party certification organizations such as UL LLC demonstrates the product has gone through a rigorous evaluation and testing process, protects the manufacturer’s reputation by separating facts from fiction and ensures ongoing commercial success.