21-0412 Use of WT-003 and Accounting for Graywater

Question

4420 Campbell Drive was flagged by a Los Angeles code official for our use of greywater at the property. We installed a laundry-to-landscape system legally without a permit per California Plumbing Code. To correct the issues, we are required to have an inspection from the city to verify the laundry to landscape greywater system follows the California Plumbing Code. The property gets all its potable water from Atmospheric Water Generators (AWG). The AWG are installed using best practices including airgaps from municipal supplied water sources, this AWG system is self-contained on the property. However, AWG technology is currently not permitted under the current codes. In preparation and during the greywater city inspection we disconnected the AWGs and are currently connected to the city water supply. City water is supplying the following water end uses on the property:

  • Kitchen sink
  • Bathroom sink
  • Shower
  • Laundry
  • Outdoor sink
  • No water from the city was directly used for irrigation, all water for irrigation was supplied by greywater or rainwater. Under the codes and LBC guidelines we can/should only use non-potable water (rainwater or treated greywater) for laundry. How can demonstrate or comply with LBC given that we will be using city water for laundry and all other potable water uses during this short period of time?

    Per LBC Handbook "100% of water demand through site-sourced water for a continuous 12-month performance period."

    Our vision/goal for this property was not to be connected to the city water supply but given the situation we are going to use the WT-003 exception, allowing for municipal water connection.

    WT-003 Municipal Potable Water Supply - Exception

    "If health regulation require project use municipal water source, IT IS ALLOWED, but only for potable uses including sinks, faucets, janitorial uses, and showers. While it is not required, the project is encouraged to include full rainwater harvesting capacity in anticipation of future regulatory acceptance of additional rainwater use."

    "To use this exception, project team must meet the minimum advocacy requirements (pg. 157)"

    Supplemental Information 

    No potable water has been used for laundry or will be used for laundry. Potable water is only being used for shower & sink water, per Los Angeles requirements. All the laundry water needs have and will continue to be met with treated AWG/Rainwater in line with Los Angeles requirements. The water diagram attached is the accurate representation of what is installed on site and has been used during our compliance period.

    Answer

    The project team has provided supplemental information, including a complete water flow schematic, which clarifies that:

    • local code does not permit any non-municipal sources of potable water, and
    • none of the municipal water supply is being used for non-potable uses.

    The project may use WT-003 Municipal Water Exception as requested. It must meet the minimum advocacy requirements as listed in the Water Petal Handbook

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