PART 6: Water Efficiency

Water Efficiency Credit Category in LEED

Overview

  • The water efficiency credit category in LEED addresses water use holistically and categorizes it into indoor, outdoor, and process water use.

  • Promotes the concept that water efficiency is crucial for sustainable building practices.

  • Encourages teams to focus on metering to track actual water usage and improve efficiency.

Types of Water

  • Potable Water:

    • Treated water suitable for human consumption.

    • Requires significant resources for treatment and distribution, hence is more energy-intensive.

  • Non-Potable Water:

    • Reclaimed or recycled water used for non-consumptive purposes (irrigation, cooling towers, etc.).

LEED Approach

  • Efficiency First:

    • Each prerequisite focuses on enhancing water efficiency specifically and reducing potable water use.

    • Credits awarded for using non-potable and alternative water sources.

Average Water Use

  • The average American uses approximately 100 gallons of water per day.

  • Highlights the increasing scarcity and cost of water as a resource.

Goals of Water Efficiency Credit Category

  • Improve Indoor Water Use:

    • Covers fixtures for urinals, toilets, showers, sinks, and other typical applications in occupied buildings.

  • Improve Outdoor Water Use:

    • Focuses on conserving water used for landscaping and irrigation, which is a significant component of water use in commercial buildings.

  • Improve Process Water Use:

    • Addresses water used in industrial processes, systems (cooling towers, boilers, chillers), and business operations (washing machines, dishwashers).

  • Meter and Monitor Water Use:

    • Encourages metering systems to track consumption trends, fixture performance, and identify leaks.

Best Practices for Indoor Water Use

  1. Install Efficient Plumbing Fixtures:

    • High efficiency lavatories, kitchen sinks, showers, dual flush toilets, waterless urinals, and composting toilets.

    • Fixtures should comply with standards set by the Energy Policy Act of 1992.

    • Consider EPA WaterSense and Energy Star certified products for selection.

  2. Utilize Non-Potable Water:

    • Implement sources such as rainwater, graywater, or reclaimed water for flush fixtures where permissible.

    • Graywater: Used water from sinks and faucets, acceptable for irrigation purposes.

    • Reclaimed Water: Water that has been highly treated, usually sourced from municipal wastewater treatment plants.

  3. Install Submeters:

    • Install submeters to monitor indoor water systems, track consumption trends, assess fixture performance, and identify leaks.

Best Practices for Outdoor Water Use

  1. Reduction in Irrigation:

    • Specifying water-efficient landscaping and irrigation technology.

  2. Choose Locally Adapted Plants:

    • Utilize native plants that require less water, also providing habitat for local wildlife.

    • Implement Xeriscaping, which involves landscaping with indigenous plantings suited to the local climate, minimizing or eliminating irrigation needs.

  3. Select Efficient Irrigation Technologies:

    • Implement drip and bubbler irrigation systems.

    • Utilize weather-based controllers to optimize irrigation timing and reduce waste.

    • Acknowledge that spray irrigation can result in water loss through evaporation.

  4. Avoid Contributions from Potable Water:

    • Use non-potable sources such as captured rainwater, graywater, or municipal reclaimed water.

  5. Install Submeters:

    • Meter irrigation systems to track water consumption and detect leaks.

    • Key Concept: "You can't manage what you don’t measure."

Conclusion

  • The LEED water efficiency credit category's main goals are to improve water usage across indoor, outdoor, and process applications while emphasizing the importance of metering and monitoring for effective resource management.

  • Green building strategies are interconnected across these areas of water usage, driving innovation and efficiency.