WE: Building-Level Water Metering (Prerequisite + Credit)
Measure everything โ Then optimize what matters most
Why This Matters
โYou canโt manage what you donโt measure.โ
LEED emphasizes measurement first, because:
- tracking โ identifies inefficiencies
- data โ drives future savings
- accountability โ supports long-term performance
๐งฉ Prerequisite vs Credit (Quick Comparison)
Requirement | Prerequisite | Credit |
Mandatory? | โ Yes | โ No |
Points | 0 | 1 |
Scope | Whole building | Subsystems |
Data Sharing | 5 years | Ongoing (monthly) |
Meter Type | Total building water | Specific uses |
๐ฐ WE Prerequisite: Building-Level Water Metering
Intent
๐ Track total building water use to support long-term water management
๐ Requirements
Projects must:
โ 1. Install permanent meters
- measure total potable water use
- includes:
- building
- associated grounds
โ 2. Record and summarize data
- monthly
- annually
โ 3. Share data with USGBC
๐ For 5 years
Starting from:
- certification acceptance OR
- typical occupancy
(whichever comes first)
โ ๏ธ Important Exam Detail
๐ Data sharing continues for 5 years:
- OR until ownership/tenant changes
๐ง What This Really Means
๐ This prerequisite is about:
- accountability
- performance tracking
- post-occupancy validation
๐ง WE Credit: Water Metering
Intent
๐ Track specific water uses to identify savings opportunities
๐ Requirement
๐ Install meters for at least TWO subsystems
๐ง Eligible Subsystems (VERY TESTABLE)
๐ฟ 1. Irrigation
๐ Must cover:
๐ โฅ80% of irrigated landscape area
๐ฝ 2. Indoor Plumbing Fixtures
๐ Must cover:
๐ โฅ80% of fixtures
(from Indoor Water Use Reduction scope)
๐ฅ 3. Domestic Hot Water
๐ Must cover:
๐ โฅ80% of system capacity
Includes:
- storage tanks
- on-demand heaters
๐ญ 4. Process Water
๐ Must cover:
๐ โฅ80% of expected daily use
Examples:
- dishwashers
- clothes washers
- pools
- humidification
โป๏ธ 5. Reclaimed Water
๐ Must be metered:
๐ 100% (regardless of volume)
๐ง 6. Boiler Water
๐ Required if:
๐ โฅ100,000 gallons/year
โ ๏ธ Critical Rules (EXAM FOCUS)
๐ด Rule 1:
๐ Must meter at least TWO subsystems
๐ด Rule 2:
๐ Most systems require 80% coverage
๐ด Rule 3 (VERY IMPORTANT):
๐ Reclaimed water:
Must ALWAYS be metered (no % threshold)
๐ด Rule 4:
๐ Must share data with USGBC:
๐ Monthly
๐ด Rule 5:
๐ Meters must be:
- permanent
- accessible
๐ง Common Misconceptions
โ โOnly whole building metering is enough for creditโ
๐ No
๐ Thatโs the prerequisite
โ โAll subsystems must be meteredโ
๐ No
๐ Only two or more
โ โ80% applies to everythingโ
๐ Not always
๐ Exception:
- Reclaimed water = 100%
โ โData sharing is optionalโ
๐ No
๐ Required for:
- prerequisite (5 years)
- credit (monthly reporting)
Official FAQs
How long must projects share whole-building water data?
How many subsystems must be metered for the credit?
A project meters irrigation (80%) and domestic hot water (80%). Does it qualify?
A project meters only indoor fixtures (80%). Does it qualify?
Needs at least 2 subsystems
Why is submetering important beyond whole-building metering?
โข identifies high-use systems
โข enables targeted improvements
โข supports operational efficiency
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