Bench marking for Option 2.

Hi Tiffany, Option 2 requires tracking water use as collected by your water meters. USGBC hasn't developed a calculator, but you can put together a simple spreadsheet for tracking this information. ENERGY STAR Portfolio Manager is another good option. The calculation is just a simple comparison of 1 year's worth of "baseline" metered water use versus 1 year's worth of "performance period" (e.g. current) metered water use. The calculations do get more involved if there are changes in occupancy since you'll have to normalize the water use data. The basic calculation formula is covered in the Reference Guide in the "Calculations" section. I'd say that 99.9% of projects pursue Option 1, and that's part of why the tools and guidance are more developed for that path.

Hi - thanks all for opening up this discussion. I have a few questions re the Option 2 route that relate to Tiffany's inquiry. 1. For a project pursuing LEED EBOM certification, I already have 1 years worth of (month-by-month) water meter readings. So, to establish the baseline performance so I just need to sum up the total water used each month or should I average out the monthly readings?  2. The meter readings I have are from the main utility meter which includes indoor water use (for normal + process water used for commercial appliances) in addition to outdoor water use. Will these readings work or do I need to actually submeter only indoor water used for flow and flush fixtures? (the latter option is problematic as it may require retrofitting some submeters). Thanks,
Shakir