Water and Materials Efficiency
Water efficiency
Know indoor water-use reduction strategies: low-flow fixtures (toilets, urinals, faucets, showerheads), WaterSense labels, submetering, leak detection, and rainwater/greywater harvesting. Outdoor strategies: xeriscaping, drip irrigation, soil moisture sensors, and ET-based controllers. Understand water balance concepts and net-zero water as an annual balance of supply and discharge.
Materials and lifecycle
Concepts: life-cycle assessment (LCA) and embodied carbon, environmental product declarations (EPDs), recycled content, regional materials, rapidly renewable materials, durability, and construction waste diversion. Recognize whole-building LCA versus material-level claims, and biogenic carbon accounting nuances.
Traps
- Assuming low-flow fixtures always save - behavior and leakage can dominate.
- Ignoring irrigation and cooling tower water, which often exceed indoor use.
- Treating recycled content as equivalent to low embodied carbon - they differ.
- Comparing LCAs with different system boundaries or functional units.
- Forgetting transport and end-of-life in material comparisons.
Worked example
An office with 200 occupants at 20 gal/person/day baseline uses 4,000 gal/day. Low-flow fixtures cut indoor use ~35% → 1,400 gal/day saved. If cooling-tower makeup is 2,000 gal/day, total savings are diluted; address the tower too. Rule of thumb: measure the whole water balance before claiming savings, and align LCA comparisons on the same functional unit and boundary.