ASSE 1087 Overview

Sept. 30, 2021

Standard fills need

About the author:

Ryan Prince is director of product certification–water systems for IAMPO. Tina Donda is vice president – water systems for IAPMO R&T. Prince can be reached at [email protected] or 708.995.3321. Donda can be reached at [email protected] or 708.995.3018.


Industry standards are a great way to ensure that a company is dedicated to making quality products. Testing and certification to consensus standards means products are capable of meeting rigorous requirements that challenge the integrity of a product. The different reasons standards are created may include, but are not limited to, industry driven motivations, political pushes or regulatory needs. In the case of ASSE 1087, it was a combination of a few of these items.

To start, some inspectors in California were requiring companies to provide evidence of NSF/ANSI 44 certification on commercial water softeners. While to a novice this may appear to be a great idea, in its scope NSF/ANSI 44 very specifically states it is dedicated to only residential applications. Therefore, commercial products do not fit well under that standard. Additionally, Texas was working on backflow regulations for water softeners so the need to write a protocol popped up. Finally, because commercial water equipment does not have a diverse presence in the existing drinking water treatment standards, the industry was running into plumbing code compliance issues. While it is true there are standards available for drinking water treatment products, these standards primarily focus on residential type products; the standards that encompass commercial products only address the safety of the materials with which the products are constructed. As a result, industry leaders formed a group to create the ASSE 1087 standard to address these concerns.

The ASSE 1087 Scope

Scopes can sometimes get complicated, but in the case of ASSE 1087 it is quite simple. Any water treatment equipment used in a commercial building qualifies to be covered under the scope of the standard. This is inclusive of point-of-entry (POE) and point-of-use (POU) applications connected to building plumbing to improve the water quality characteristics of potable water. This standard includes testing requirements for components and complete systems. A few examples of the types of equipment covered include filters, softeners, reverse osmosis assemblies, ultraviolet systems, ozone systems and distillers.

Eventually, we will delve into very specific details regarding what the standard covers. Before doing so, however, there is merit in discussing what is not covered by this standard and why not.

What is NOT Covered

Electrical compliance. Some products utilize electrical components. In most cases, these components must adhere to electrical compliance standards irrespective of the ASSE 1087 standard. About a decade ago, the suite of drinking water treatment standards removed verifying electrical compliance for products because there are different requirements for the different types of electrical components. Expertise for these requirements is found within labs and certification programs that perform this type of work.

Generally, there is little to no overlap between the experts in water and electric, so asking those in water to verify accurate compliance for electrical requirements was a rather arbitrary ask. Further, electrical requirements were different depending upon the country in which the product is being sold. Therefore, the electrical requirements to which a product must adhere are left out of this standard, so the proper authorities can accurately assess them.

Contaminant reduction performance. Contaminant reduction requirements may vary by location. More specifically, when large commercial systems are manufactured, they are done so to address very specific needs in the location it will be installed. As a result, the feasibility of a manufacturer being able to invest in individual certification of each configuration for reduction requirements is not a possibility. Reduction performance may be added to the standard at a later time if the industry is able to develop realistic testing protocols that will be available to all.

Residential water treatment devices. Residential water treatment products have a variety of different standards that are already being used. There are even federal and state regulations in existence that reference the drinking water treatment unit standards. Not only are some of the tests found in ASSE 1087 not applicable to residential use, including them in this standard would have been a duplication of efforts, so it was deemed unnecessary.

Standard Requirements

Listed below are individual requirements for each section of ASSE 1087.

Connections. The inlet and outlet connections of the device must conform to the appropriate ASME, ASSE or SAE standards. The appropriate standards cover various threaded assemblies, soldered connections and push fit connections, and are delineated in the 1087 standard. This is to ensure the systems can be installed properly and easily using readily available materials.

Flow rate. Service flow and pressure drop testing is required for most systems. This testing is to ensure the device can meet the manufacturer’s claims for flow rates at specific pressure drops of 15 and 25 psi. Some units are exempt, such as reverse osmosis systems and devices being certified as components.

Bypass flow capacity is required on certain products, such as cation exchange water softeners that have a regeneration cycle. This is to ensure there is still adequate service flow of untreated water during the regeneration cycle. The bypass flow rate must be at least 50% of the measured service flow rate.

Backsiphonage. Testing for bask-siphoning during system regeneration is required on products such as cation exchange water softeners that use brine to regenerate the system. This is to ensure the brine is not pulled back into the water source. Devices that include a certified backflow prevention device may be exempt from this requirement. This test is run by pulling a vacuum on the inlet of 12.3 psi and measuring the vertical rise in the fluid level from the brine tank. Systems must have less than 3 inches of vertical rise.

Structural integrity. There are four tests required to verify the structural integrity of the system or component.

  1. 24-hour pressure loss test. This test is to ensure all the device’s seals, joints and connections continue to maintain the static working pressure. It is run at 50 psi, and the unit may not lose more than 3 psi over the 24-hour period.
  2. Pressure shock (water hammer) test. This test is to determine if the device can withstand the pressure shockwave from rapidly closing a valve in the downstream piping. This test must be run such that the shockwave produces a recordable pressure of two-times the manufacturer’s maximum working pressure, or 200 psi, whichever is greater.
  3. Hydrostatic test. This test is to ensure the system will be able to withstand the peak pressures found within the plumbing system. When tested, the pressure will gradually rise until it reaches three-times the manufacturer’s maximum working pressure, or 300 psi, whichever is greater, and the system must hold that pressure for 15 minutes without breaking, cracking or leaking. Minor drips would not constitute a failure.
  4. Cycle test. This test is performed to ensure the system will be able to withstand repeated pressure cycling. Systems must withstand 100,000 cycles from 0 psi to the maximum working pressure plus 10 psi, or 150 psi, whichever is greater. Any breaking, cracking or leaking constitutes a failure; minor drips are acceptable.

Material safety. Material safety testing, also known as extraction testing, is required to be evaluated for all the wetted components of the system. This testing refers to existing standards, such as NSF/ANSI 42 or NSF/ANSI/CAN 61. In general, most units can be tested as a complete system, but in cases where the size of the system may prevent testing in this manner, it is also possible to verify compliance of individual components through a technical review of the wetted parts list.

All systems and components must also comply with the low-lead requirements of NSF/ANSI/CAN 372. This is now a federal requirement for all new products; including this in the standard ensures the system complies with federal laws.

Literature and documentation requirements. There are two key literature and documentation items required per the standard. The first is the installation and maintenance instructions. This must include information such as the inlet and outlet connection sizes, maximum working pressures, recommended flow rates, replacement component part numbers and information, and key information regarding drain connections and air gap requirements. This information is to ensure the installation is completed per the manufacturer’s intent and that the system operates correctly.

The second item is the identification and marking requirements. This requirement is typically with a data label, and it must include information such as the name of the manufacturer, model number of the system, working temperature and pressure ranges, and the service flow rates. The inlet and outlet connections must also be clearly marked. Any labels used must comply with UL 969 to ensure they remain in place permanently.


The ASSE 1087 standard filled a gap that was missing in the water treatment product industry. A great deal of time and effort was dedicated to ensuring it provides good protocols to ensure safety for products that are being used to convey treated drinking water in commercial environments. ASSE 1087 was recently adopted into the plumbing codes, so understanding and complying with these requirements will become increasingly more critical as inspectors begin looking for these types of products to be certified moving forward.

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