NSF/ANSI 40: Residential Onsite Systems

  • Overview
  • Testing Process
  • Benefits of Certification
  • Why Work With NSF?
  • Certification Process

NSF/ANSI 40 is a standard for residential wastewater treatment systems with rated capacities between 400 and 1,500 gallons (1,514 and 5,678 liters) per day. We can evaluate any kind of system, regardless of treatment technology, in test facilities in the U.S., Canada and Europe.

To achieve certification, treatment systems must produce an acceptable quality of effluent during a six-month (26-week) test. Class I systems must achieve a 30-day average effluent quality of 25 mg/L CBOD5 and 30 mg/L TSS or less, and pH 6.0-9.0 spanning six months of testing. System service and maintenance are prohibited during the test period.

Testing Process

Wastewater of required strength is introduced to the treatment system at the rated system capacity in even doses at prescribed periods. Stress sequences simulate wash day, working parent, power outage and vacation scenarios.

The effluent criteria required of a Class I system is based on the U.S. EPA secondary effluent treatment requirements for municipal treatment facilities.

In addition to effluent performance, requirements also exist for product literature, including installation, operation, maintenance, troubleshooting and repair manuals. The system must also meet minimum requirements for structural integrity, leakage, noise, electrical certification, access ports, failure sensing and signaling equipment (visual and audible alarms), flow design, data plate and service labels.

Benefits of Certification

NSF/ANSI 40 is the most recognized and required standard for the residential wastewater treatment industry with more than 30 years of market use and acceptance. Certification to NSF/ANSI 40 provides your company access to the onsite residential wastewater market.

The regulatory community also benefits from NSF/ANSI 40 and other NSF wastewater standards. Recognizing that public health officials have the ultimate authority in approving wastewater treatment systems, we provide easy access to public listings of certified products, as well as direct access to product evaluation reports and data, complaint procedures for products or companies of concern, training materials and more. Federal, state and local agency representation on the standard’s joint committee ensures that the interests of health officials are central to product certification.

Certification also allows your company to:

  • Distinguish your product in the marketplace by demonstrating its performance through independent evaluation
  • List your product and company in our online directory of certified treatment systems
  • Use the NSF certification mark on your systems and in your promotional materials

Why Work With NSF?

NSF International is a trusted name in onsite wastewater systems certification. We create standards and protocols, test and certify products and provide inspector accreditation. Our services deliver confidence to consumers, assurance of performance to public health officials and market access for product manufacturers in the onsite wastewater treatment industry.

NSF/ANSI 40 is the most recognized and required standard for this industry with more than 30 years of market use and acceptance.

Products that comply with the requirements of the standard may use the NSF mark, one of the best known and trusted certification marks in the wastewater industry. The mark is not an approval of the equipment, but indicates certification of the data provided by the test and compliance with the requirements of the standard.

Certification Process

Initial Certification

  1. Your company submits an application.
  2. NSF reviews general information, drawings and design specifications of the treatment system.
  3. NSF installs the unit at our test facility and performs thorough testing.
  4. NSF issues a final test report.
  5. NSF reviews product literature, data plates, service labels and related documentation.
  6. NSF performs an initial audit of the manufacturing facility.
  7. Upon gaining certification, your company may use the NSF mark on your product, packaging and promotional materials.

Continued Certification

  1. NSF performs an annual audit of the manufacturing facility and in some cases authorized representatives.
  2. NSF reevaluates and potentially retests products at least once every seven years.
  3. NSF reviews and approves any product modifications.

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