NC-v5 WEc2: Enhanced Water Efficiency 8 points

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Intent

To reduce potable water consumption and the associated energy consumption and carbon emissions required to treat and distribute water, and to reward use of alternative water sources that preserve potable water resources.

Requirements

Implement a combination of the following strategies for a maximum of 8 points. Projects may either attempt Option 1 or any combination of Options 2–6.

Option 1. Whole-Project Water Use (1–8 points)
To pursue this pathway, project teams must develop a water use baseline and create a proposed use model. Points are achieved based on reductions from the baseline in Table 1.

Table 1. Points for Reducing Overall Project Water Use

OR

Option 2. Fixture and Fittings — Calculated Reduction (1–3 points)
Further reduce fixture and fitting water use from the calculated baseline in WEp2: Minimum Water Efficiency, Minimum Fixture and Fittings Efficiency, Path 2. Performance Path — Calculated Reduction. Additional potable water savings can be earned above the prerequisite level using alternative water sources. Points are awarded according to Table 2.

Table 2. Points for Reducing Indoor Water Use

AND/OR

Option 3. Appliance and Process Water (1–2 points)
Newly installed equipment within the project boundary must meet the minimum requirements in Tables 3, 4, 5, and/or 6. One point is awarded for meeting all applicable requirements in any 1 table for a maximum of 2 points. All applicable, newly installed equipment listed in each table must meet the standard. Existing appliances and equipment can be excluded.

To use Table 3, the project must process at least 120,000 lb (57,606 kg) of laundry per year.

Table 3. Compliant Commercial Washing Machines

^{*Based on equal quantities of heavily, medium, and lightly soiled laundry.}

To use Table 4, the project must serve at least 100 meals per day of operation.

Table 4. Standards for Compliant Commercial Kitchen Equipment

_{Note: gpm = gallons per minute; lpm = liters per minute.}

Table 5. Compliant Laboratory and Medical Equipment

To use Table 6, the project must be connected to a municipal or district steam system that does not allow the return of steam condensate.

Table 6. Compliant Municipal Steam Systems

AND/OR

Option 4. Outdoor Water Use (1–2 points)
PATH 1. NO IRRIGATION (2 POINTS)
Show that the landscape does not require a permanent irrigation system beyond a maximum two-year establishment period.

OR

PATH 2. EFFICIENT IRRIGATION (1–2 POINTS)
Reduce the project’s theoretical irrigation requirement (TIR) by at least 50% from the calculated baseline. Points are awarded according to Table 7.

Table 7. Points for Reducing Outdoor Water Use

AND/OR

Option 5. Optimize Process Water Use (1–2 points)
PATH 1. LIMIT COOLING TOWER CYCLES (1–2 POINTS)
For cooling towers and evaporative condensers, conduct a one-time potable water analysis, measuring at least the five control parameters listed in Table 8.

Table 8. Maximum Concentrations for Parameters in Condenser Water

_{Note: ppm = parts per million; µS/cm = micro siemens per centimeter.}

Calculate the maximum number of cooling tower cycles by dividing the maximum allowed concentration level of each parameter by the actual concentration level of each parameter found in the potable makeup water analysis. Limit cooling tower cycles to avoid exceeding maximum values for any of these parameters.

The materials of construction for the water system that contact the cooling tower water must be of the type that can operate and be maintained within the cycles established in Table 9. Points are awarded according to Table 9.

Table 9. Points for Cooling Tower Cycles

Projects whose cooling is provided by district cooling systems are eligible to achieve Path 1 if the district cooling system complies with the preceding requirements.

OR

PATH 2. OPTIMIZE WATER USE FOR COOLING (1–2 POINTS)
To be eligible for Option 2, the baseline system designated for the building using ASHRAE 90.1-2019 or 90.1-2022, Appendix G, Table G3.1.1-3, must include a cooling tower (systems 7, 8, 11, 12, and 13).

Achieve increasing levels of cooling tower water efficiency beyond a water-cooled chiller system with axial variable-speed fan cooling towers having a maximum drift of 0.002% of recirculated water volume and three cooling tower cycles. Points are awarded according to Table 10.

Table 10. Points for Reducing Annual Water Use Compared to Water-Cooled Chiller System

Projects whose cooling is provided by district cooling systems are eligible to achieve Path 2 if the district cooling system complies with the preceding requirements.

OR

PATH 3. PROCESS WATER USE (1–2 POINTS)
Demonstrate that the project is using a minimum of 20% alternative water to meet the process water demand for 1 point or that the project is using a minimum of 30% alternative water to meet process water demand for 2 points. Ensure that alternative water is of sufficient quality for its intended end use.

Process water uses eligible for achievement of Path 3 must represent at least 10% of total building regulated water use and may not include water used for cooling. 

AND/OR

Option 6. Water Reuse (1–2 points)
PATH 1. REUSE-READY SYSTEM (1 POINT)
Install a water supply system to allow the supply of reclaimed or alternative water to reach one or more of the following end uses. Space shall be provided for treatment equipment as applicable to end uses.

OR

PATH 2. ALTERNATIVE WATER SOURCES (2 POINTS)
Incorporate one of the following water reuse strategies for indoor, outdoor, and/or process water that meets the needs of one or more end uses for the building and grounds:

• On-site water reuse system
• Municipally supplied reclaimed water

Eligible end uses for Paths 1 and 2 include irrigation, flush fixtures, makeup water systems (such as cooling towers or boilers), or other process water systems.