Understanding NSF and ANSI Water Quality Certifications 

NGOs, government bodies like the CDC, and the World Health Organization (WHO) have set standards for water quality. We shall be discussing in broader terms, the qualities desired in potable water and the standard set forth for maintaining and measuring that quality.

To test the quality of water, the below properties are taken into consideration:

  • Presence of radioactivity
  • Biological aspects
  • Physical characteristics
  • Chemical qualities

Treated water should be friendly towards the below parameters:

  • Safety of human consumption (drinking and cooking)
  • Health of the environment/local ecosystem
  • Safe for infrastructure (piping, faucets, etc.)

Various governments have fixed norms for the supply of water-based on these standards and these quite often regulate the option for distribution. To maintain the best practices in the treatment of water, there are certain standards that the equipment used to process water should maintain. There are authentic bodies that inspect each of the tools that require certification and issue licenses based on the results.

While governments might indicate safe levels of water contaminants, independent bodies like the NSF and ANSI are tasked with measuring the effectiveness of specific products and setting certifications for things like water filters.

Let us take a close look at the standards and certifications applied to assess the performance of various pieces of equipment and systems used to treat water.

Water Standard For Filters


NSF/ANSI 42 is the standard that has to do with making water taste good. NSF 42 covers water filters that are used both at the source (the public water supply) as well as at a home’s faucet to minimize odor and taste variations caused by chemicals like chlorine. It is an “aesthetic” standard as opposed to a safety one.


Another standard used to certify filters is its power of absorption and capacity for filtration. This can vary in filters from different manufacturers. The testing decides whether a particular filter is good enough to absorb undesirable materials contained in the water.

Softeners for Treating Hard Water


Branded softeners that get activated by the right use of potassium chloride or sodium are common substances for treating hard water. The chemicals that usually make water hard are primarily magnesium and calcium.

The action of a good softener substitutes magnesium and calcium ions with potassium or sodium ions.

Disinfecting Class A Systems


Water is, unfortunately, and ideal habitat for microorganisms like microbial cysts, viruses, and bacteria.

Many water-borne diseases can be controlled by eliminating these parasites from drinking water. UV treatment is a time-proven technique to kill undesirable microbes in the water. The water passes through ultraviolet light with a standard frequency that will kill these malevolent tiny life forms. The systems used in these processes are tested to assess their effectiveness.

Reverse-Osmosis (RO) Certifications


Although the process of filtration using reverse osmosis technology is simple, manufacturers use extra sieves at the entry point to the system and at the exit to ensure greater results. The systems used in the RO processes require a license.

Certification for Distillation Systems


Water distillation is an effective and time proven technique to remove unwanted substances to increase its purity. If the distillation equipment does not meet certain standards, it causes certain harmful substances to get dissolved into the distilled water. Certifications issued after proper evaluation and testing of the distillation equipment removes this possibility.

Shower Filter Certification


These certifications are issued after testing the shower filters for home use. The inspection is to assess the capacity of the filter to substantiate minimize chlorine content.

Public Supply Filters


The effectiveness of filters used on public supply lines to shield against intermittent microbiological contamination is tested to issue this certificate.

Treatment Systems


Water can contain ’emerging contaminants’ that have not yet come under the purview of Health Canada or the EPA. Some systems control this.

Filters at Point-of-Use

NSF P477

They are effective in controlling wastes emanating from certain types of algae present in the water.

Material Safety Systems

NSF P473

There is a regulation that clearly defines the amount of PFOS and PFOA permitted in potable water. There are special systems used to achieve these standards and structural obligations.

Purifier Certifications

NSF P231

The task force report of EPA has laid out clear guidelines for the standards of microbiological filters.

Isotope Removal Systems


There is an international norm to treat the presence of iodine in water. A process called ‘Iodine radioisotope point-of-use treatment’ is used to remove iodine.

Certification by a competent authority ensures the efficiency of systems used to treat water. The process of treatment and the equipment used determines the quality of water.