How to meet the WELL v2.0 Standards for water

In production: Omicron filtration systems to deliver WELL Water Feature W01 in NYC water conditions.


The International Well Building Institute (IWBI) created the WELL Building Standard to identify qualitative benchmarks that make building environments healthier for people who live or work in them. 

    With the recent release of WELL v2.0, we think it may be useful to share our views on how the Water Features apply specifically to New York City water conditions.  Our goal is to explain how owners and engineers can best specify water technologies to efficiently and reliably meet the contaminant threshold requirements established by IWBI.

    The full list of requirements are found here:

    (Note: Wellness is a value in its own right, not limited specifically to WELL compliance.  There is intrinsic merit in using water tech to assure water quality, whether or not the project is building according to WELL.)

    Because WELL has a global perspective, interpreting the Standard consistent with local conditions and variables can be challenging.  Compliance with WELL Water Features further poses a special set of complications, for three principal reasons:

    1. Water conditions are highly variable, from moment to moment and place to place.
    2. Responding correctly to the Features requires an understanding of the actual significance of the water quality factors stated.
    3. Designating water technologies to deliver water quality consistent with WELL demands knowledge of the equipment's operational parameters, as well as applicable codes and regulations.

    There are three Preconditions in the Water Features that must be met in order to qualify for WELL certification:

    1. Feature W01: Fundamental Water Quality
    2. Feature W02: Water Contaminants
    3. Feature W03: Legionella Control.  

    The first two can be addressed with correct technologies.  The third requires a narrative from the project team (which is outside the scope of this post).

    Feature W01: Fundamental Water Quality


    What's the impact? 

    Over the course of our 20+ years of experience, we have found NYC water often presents Turbidity at a level greater than 1.0 NTU.  The value we typically find at the domestic water supply to buildings ranges between 1 and 3 NTU.  

    At left is a recent NTU reading of water drawn from a Manhattan building's domestic water.

    Two calls to action: 

  1. 1.  Reducing Turbidity to under 1.0 NTU requires at minimum no coarser than 10 micron filtration.  See before / after readings below.
  2. 2.  Reliable 10 micron filtration requires a correct ratio of flow rate to screen area.
  3. NTU reading of unfiltered water before Omicron 10, Manhattan NTU reading after Omicron 10 filtration (same location) 

    Upshot:  In expected NYC water conditions correctly sized 10 micron filtration is required to meet the W01 Part 1 Feature. 

    Feature W02: Water Contaminants

    This Feature, Part 1 through Part 5, identifies numerous water-borne contaminants that must be addressed with respect to the stated threshold values.  (To review these, scroll to the bottom of this post or click here:)

    What's the impact?

    Of the identified factors, in fact only a minority are actually present in NYC water to begin with.  And of these, few if any are detected at levels that exceed their respective threshold values.  You can verify this information via this report from National Testing Labs or the Water Testing Report.

    Therefore to meet the W02 Feature Parts 1 - 5 in expected NYC water conditions, no additional technologies are indicated.

    That said, it is easy to get an additional WELL point by meeting the conditions of Feature W05: Water Quality Consistency, Part 2.



    The above requirements are fulfilled entirely by the XL7000 filtration system at points of use.The National Testing Labs report referenced above illustrates the efficacy of the XL7000 on those factors that compromise water quality.

    Of the seven contaminants that present in actual NYC water conditions,  every one is reduced to "ND" (not detected) by the XL7000. For clarity these seven are shown in red in the tap water report, and in green in the filtered water report. (I.e. before / after filtration).


    Level in tap water
    After XL7000 filtration
    0.132 mg/L 
    0.028 mg/L 
    0.010 mg/L 
    0.005 mg/L
    0.7 NTU*
    Bromodichloromethane (THM)
    0.005 mg/L
    Chloroform (THM)
    0.036 mg/L 

            * Nephelometric Turbidity Units (NTU) is a measure of water clarity.

    Please note an important exception and omission within Feature W02, Part 6:

    What's the impact?

    The chlorine threshold above is significantly different from all other water quality factors shown.  NYC tap water is meant to hold chlorine at the level of 4 mg/L, per threshold stated.  Since the additive enters the water supply long before it reaches a building's water supply, the actual level will fluctuate.

    Unlike all the other water quality factors identified, some level of chlorine is essential for domestic water circulating within a public or multi-residential building to prevent pathogen growth in the lines. In our opinion, the v2 Standards should note that a minimum level is also recommended -- not just a "do not exceed" maximum.

    While there is clearly no requirement to remove chlorine from the domestic water supply to a building, there is every good reason to remove it, along with those other contaminants that comprise the difference between tap water and "bottled quality", at point of use.

    In conclusion, in NYC water conditions:

    • to comply with WELL v2 Feature W01 and W02, specify an Omicron 10 micron filter for the building (point-of-entry) correctly sized to the max flow rate.
    • to get an extra point from Feature W05, specify the XL7000 at drinking water outlets (point-of-use).

    Note: Some engineers and owners have been advised by a vendor to use a product by Triple Clear as a secondary stage filtration product.  With the above information it should be clear why this is unnecessary.  Read more.

    For more information about Omicron technologies and application considerations, please see Specifications and additional articles in our Knowledge Base.

     WELL v2 Feature W02, Parts 1-5: