WE: Building-Level Water Metering (Prerequisite + Credit)
Measure everything → Then optimize what matters most
Why This Matters
“You can’t manage what you don’t measure.”
LEED emphasizes measurement first, because:
- tracking → identifies inefficiencies
- data → drives future savings
- accountability → supports long-term performance
🧩 Prerequisite vs Credit (Quick Comparison)
Requirement | Prerequisite | Credit |
Mandatory? | ✅ Yes | ❌ No |
Points | 0 | 1 |
Scope | Whole building | Subsystems |
Data Sharing | 5 years | Ongoing (monthly) |
Meter Type | Total building water | Specific uses |
🚰 WE Prerequisite: Building-Level Water Metering
Intent
👉 Track total building water use to support long-term water management
📏 Requirements
Projects must:
✅ 1. Install permanent meters
- measure total potable water use
- includes:
- building
- associated grounds
✅ 2. Record and summarize data
- monthly
- annually
✅ 3. Share data with USGBC
👉 For 5 years
Starting from:
- certification acceptance OR
- typical occupancy
(whichever comes first)
⚠️ Important Exam Detail
👉 Data sharing continues for 5 years:
- OR until ownership/tenant changes
🧠 What This Really Means
👉 This prerequisite is about:
- accountability
- performance tracking
- post-occupancy validation
💧 WE Credit: Water Metering
Intent
👉 Track specific water uses to identify savings opportunities
📏 Requirement
👉 Install meters for at least TWO subsystems
🔧 Eligible Subsystems (VERY TESTABLE)
🌿 1. Irrigation
👉 Must cover:
👉 ≥80% of irrigated landscape area
🚽 2. Indoor Plumbing Fixtures
👉 Must cover:
👉 ≥80% of fixtures
(from Indoor Water Use Reduction scope)
🔥 3. Domestic Hot Water
👉 Must cover:
👉 ≥80% of system capacity
Includes:
- storage tanks
- on-demand heaters
🏭 4. Process Water
👉 Must cover:
👉 ≥80% of expected daily use
Examples:
- dishwashers
- clothes washers
- pools
- humidification
♻️ 5. Reclaimed Water
👉 Must be metered:
👉 100% (regardless of volume)
💧 6. Boiler Water
👉 Required if:
👉 ≥100,000 gallons/year
⚠️ Critical Rules (EXAM FOCUS)
🔴 Rule 1:
👉 Must meter at least TWO subsystems
🔴 Rule 2:
👉 Most systems require 80% coverage
🔴 Rule 3 (VERY IMPORTANT):
👉 Reclaimed water:
Must ALWAYS be metered (no % threshold)
🔴 Rule 4:
👉 Must share data with USGBC:
👉 Monthly
🔴 Rule 5:
👉 Meters must be:
- permanent
- accessible
🧠 Common Misconceptions
❌ “Only whole building metering is enough for credit”
👉 No
👉 That’s the prerequisite
❌ “All subsystems must be metered”
👉 No
👉 Only two or more
❌ “80% applies to everything”
👉 Not always
👉 Exception:
- Reclaimed water = 100%
❌ “Data sharing is optional”
👉 No
👉 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?
• identifies high-use systems
• enables targeted improvements
• supports operational efficiency
Comments
No comments yet. Be the first to post!
