Hello,
Our project is an office building where dedicated toothbrushing faucets will be installed in restrooms, separately from regular lavatory faucets.
Since these toothbrushing faucets serve a different purpose from regular lavatory faucets, we believe their water use may need to be calculated separately.
Has anyone encountered a similar situation or received any LEED review comments regarding how dedicated toothbrushing faucets should be accounted for in the Indoor Water Use Reduction Calculator?
We are currently considering the following two approaches:
- Split the usage percentage under Public Lavatory Faucets: Allocate the percentage of occupants between regular lavatory faucets and toothbrushing faucets so that the combined total equals 100%, without adding any additional daily uses.
- Calculate toothbrushing faucet water use separately as additional consumption: Complete the standard Indoor Water Use Reduction Calculator as if the dedicated toothbrushing faucets were not installed, accounting for all other plumbing fixtures as usual. Then, calculate the water consumption of the toothbrushing faucets separately in an additional calculation sheet, assuming one use per occupant per day, and add this consumption to the standard calculation. In other words, the standard usage frequencies of the existing plumbing fixtures would remain unchanged, while the water consumption associated with toothbrushing faucets would be added separately.
We would appreciate any insights or experiences from the LEEDuser community regarding which approach would be more appropriate.
Additionally, we have a question regarding graywater reuse.
Our project includes a graywater treatment system that collects and treats wastewater from designated plumbing fixtures for reuse in water closets and urinals.
We are considering calculating the daily potable water offset from graywater reuse as the minimum of the following three values:
- Available graywater volume: The daily volume of wastewater generated from the plumbing fixtures connected to the graywater treatment system.
- Graywater storage tank capacity: The storage capacity of the graywater tank.
- Daily flushing water demand: The daily water demand for flushing water closets and urinals.
Would this be an appropriate method for determining the potable water offset from graywater reuse in the Indoor Water Use Reduction Calculator, or should additional factors be considered?
We would appreciate any guidance or relevant project experience regarding these calculation methods.
Thank you in advance for your help!