Indoor water use reduction

Intent

To reduce indoor water consumption.

Requirements

Option 1. Calculated Water Use

Establishment

For the indoor plumbing fixtures and fittings listed in Table 1, reduce water consumption to or below the LEED v4 for Existing Buildings: Operations & Maintenance baseline, calculated assuming 100% of the building’s indoor plumbing fixtures and fittings meet the flush and flow rates listed in Table 1.

The LEED v4 for Existing Buildings: Operations & Maintenance water use baseline is set depending on the year of building’s occupancy, as follows:

• For a building with a certificate of occupancy dated 1995 or later, the baseline is 120% of the water use that would result if all fixtures met the code requirements in Table 1.
• For a building with a certificate of occupancy dated before 1995, the baseline is 150% of the water use that would result if all fixtures met the code requirements in Table 1.

Table 1. Fixture and fitting code requirements

If indoor plumbing systems were renovated after initial occupancy of the building, set a whole-building average baseline by prorating the above limits, based on the proportion of plumbing fixtures installed during the plumbing renovations in each period. Pre-1995 buildings that have had only minor fixture retrofits (e.g., aerators, showerheads, flushing valves) but no plumbing renovations in or after 1995 may use the 150% baseline for the whole building.

Calculate fixture and fitting performance to compare the water use of the as-installed fixtures and fittings with the use of Uniform Plumbing Code or International Plumbing Code-compliant (baseline) fixtures and fittings.

Inspect all existing fittings or fixtures to ensure they are operating properly. Make any repairs needed to bring all fixtures into good working order or permanently turn off water supply to nonfunctional units.

Implement a fixture and fitting replacement and retrofit policy specifying that all newly installed toilets, urinals, private lavatory faucets, and showerheads that are eligible for labeling be WaterSense labeled (or a local equivalent for projects outside the United States).

Have in place a process and appliance water equipment purchasing policy for the building and site addressing the products listed in Table 2. The policy must cover at least those products purchased within the building and site management’s control.

Table 2. Standards for appliances

Performance

For building water use, confirm that calculations are up to date. Demonstrate that all applicable purchases made during the performance period meet the requirements of the fixture and fitting replacement and retrofit policy.

For appliances, demonstrate that appliances purchased and installed within the building meet the requirements listed in Table 2. Appliances not listed are not subject to any additional requirements.

Option 2. Metered water use

Establishment

Meter fixtures and fittings and record metered data for one year to establish a water-use baseline.

Performance

For projects with at least 80% of fixtures and fittings metered, show that the water-use baseline has been maintained.

Behind the intent

Use of potable water – water that has been treated to a quality appropriate for human consumption – in buildings constitutes a large portion of freshwater consumption. Indoor water use in the U.S. is affected by a federal standard for certain plumbing fittings and fixtures, and by the Uniform Plumbing Code (UPC). This prerequisite requires projects to use less potable water than would be allowed by the federal standard and the UPC. Reducing potable water use will result in a number of benefits to the project and to the environment.

• Conserving potable water use reduces the energy and chemicals that must be used to treat water to potable quality.
• Conservation also reduces the energy that must be expended to distribute treated water to consumers.
• Potable water conservation can allow Public Water Systems (PWS) to delay expenditures to expand water treatment capacity.
• Displacing potable water for certain purposes that do not entail human contact or consumption may lead to more sustainable management of community water resources, while decreasing building operating cost.

Strategies to reduce potable water use in buildings will entail the selection of plumbing fittings and fixtures, and water-using equipment that use less water than conventional fittings and fixtures, or the use of alternative water sources. Performance of lower flow fittings, fixtures, and equipment will be an important consideration, because unsatisfactory operation may encourage building owners and occupants to replace conserving devices with higher flow units.

Step by step guidance

Common steps

The calculation to support this prerequisite compares a design case to a baseline case.

1. Be certain to select WaterSense Fittings and Fixtures for those units that are subject to WaterSense labeling.
2. The calculation for this prerequisite is: