Wastewater Standards and Protocols

  • Overview
  • Standards
  • Protocols
  • Why Work With NSF?

NSF has over 40 years of experience in onsite wastewater treatment systems. We work with key industry stakeholders to develop standards and protocols that set the benchmarks for testing, product certification and inspector accreditation. Our standards deliver confidence to consumers, assurance of performance to public health officials and market access and acceptance for product manufacturers in the onsite wastewater industry.

Standards and protocols can provide credibility and industry acceptance for new products or emerging technologies. To find out more about developing standards or protocols, call +1 734.913.5774 or email standards@nsf.org.

For standard development or revision status, visit the NSF Online Workspace. Get involved with NSF standards and protocol development by joining a Joint Committee. The NSF Standards Department is seeking experts to serve on various NSF joint committees. Learn more.

To purchase standards, visit the NSF Bookstore website.


NSF/ANSI 350 and 350-1: Onsite Reuse Treatment Systems

NSF/ANSI Standards 350 and 350-1 establish material, design, construction and performance requirements for onsite residential and commercial water reuse treatment systems, including graywater treatment systems. Learn more about NSF/ANSI 350 and NSF/ANSI 350-1.

NSF/ANSI 40: Residential Wastewater Treatment Systems

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. Learn more about NSF/ANSI 40.

NSF/ANSI 41: Non-Liquid Saturated Treatment Systems

NSF/ANSI Standard 41 certifies composting toilets and similar treatment systems that do not use a liquid saturated media as a primary means of storing or treating wastes. Learn more about NSF/ANSI 41.

NSF/ANSI 46: Water Treatment System Components

NSF/ANSI 46: Evaluation of Components and Devices Used in Wastewater Treatment Systems evaluates the performance of wastewater treatment system components and devices such as grinder pumps, septic tank effluent filters, chlorination devices and UV disinfection devices. Learn more about NSF/ANSI 46.

NSF/ANSI 245: Nitrogen Reduction

NSF/ANSI 245: Wastewater Treatment Systems - Nitrogen Reduction defines total nitrogen reduction requirements for residential wastewater treatment systems with rated capacities between 400 and 1,500 gallons (1,514 and 5,678 liters) per day. Learn more about NSF/ANSI 245.

NSF/ANSI 240: Drainfield Product Trench Sizing

NSF/ANSI 240: Drainfield Trench Product Sizing for Gravity Dispersal Onsite Wastewater Treatment and Dispersal Systems establishes minimum material, design, construction and performance requirements to evaluate dispersal drainfield products used as alternatives to traditional stone or gravel trenches. Learn more about NSF/ANSI 240.

NSF/ANSI 360: Field Performance Verification

NSF/ANSI 360: Wastewater Treatment Systems - Field Performance Verification establishes consistent site selection, sampling, laboratory analysis and data evaluation methods for obtaining field performance results for onsite wastewater treatment systems. Learn more about NSF/ANSI 360.


NSF has developed several wastewater protocols containing customized testing criteria for validating performance and product claims. NSF wastewater protocols pertain to tissues in septic systems, incinerating toilets, solid/liquid separators and sewage sludge sterilization. Learn more about NSF wastewater protocols.

NSF P150: Tissues in Septic Systems

Protocol P150 evaluates the impact and fate of a tissue product entering a septic system. Tissues meeting the requirements of this protocol will not substantially increase sludge or scum accumulation, or substantially increase the loading of organic material and solids to the soil drain field.

NSF P157: Incinerating Toilets

NSF P157 evaluates the health and sanitation characteristics of electrical incinerating devices designed to combust toilet waste. It specifies minimum requirements for materials, design, construction, performance and cleanability.

NSF P340: Solid/Liquid Separators

NSF P340 establishes minimum requirements for health and environmental protection of septic tank or grease trap solid/liquid separating devices. The usual technique for processing septic tank sludge and retained grease and solids in grease traps is to completely remove the contents of the tank and dispose of all the liquid, solid and biological material at a municipal wastewater treatment plant or other approved disposal facility. This process involves handling of a great deal of water, requiring expensive transportation and disposal. It also removes beneficial biological flora from septic tank waste.

NSF P340 sets health and environmental requirements for systems using newer technologies to separate solids and liquids. These systems retain solids in a septic tank (or grease and solids in a grease trap) for disposal, while returning the treated water to the septic tank or grease trap.

NSF P353: Sewage Sludge Sterilization

NSF P353 establishes requirements for organically-enhanced granular fertilizer manufacturers that use sewage sludge as a replacement for water. Certification verifies that the granular fertilizer product is free of pathogens, is noncombustible and meets the pathogen reduction and metals concentration requirements for Class A conditioned sewage sludge and PFRP requirements of the 40 CFR Part 503 rule.

Why Work With NSF?

NSF has over 40 years of experience in onsite wastewater treatment systems. Our experience and industry background can help your organization with certification to existing standards or in developing new ones. NSF is accredited by the American National Standards Institute (ANSI) to develop American National Standards. ANSI's accreditation verifies that NSF develops standards in a manner that ensures openness and due process allowing for equity and fair play.

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