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ITEM: |
ACTION ITEM |
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Meeting
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March 21, 2022
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Budgeted:
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N/A
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From: |
David J.
Stoldt, |
Program/ |
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General
Manager |
Line Item No.: |
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Prepared By: |
Stephanie Locke |
Cost
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N/A |
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Committee Review: The Water Demand Committee unanimously
recommended approval of this action at its March 3, 2022, meeting.
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General Counsel Review:
N/A
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CEQA
Compliance: This action does not
constitute a project as defined by the California Environmental Quality Act
Guidelines section 15378. |
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SUMMARY: Staff asked for committee review of the water credit for installing a rainwater or Graywater plumbing system to flush toilets and/or wash laundry due to a number of complexities related to approval, installation, and operation of a system. The Technical Advisory Committee (TAC) discussed this on March 2, 2022. The TAC thought that every way to obtain credit should continue to be offered due to the lack of water availability. However, the Water Demand Committee reviewing the same topic the following day was adamant that the credit, due to the many potential problems associated with it, should be discontinued.
The Water Demand Committee recommends that the credit for installing and using a Graywater/rainwater system to flush toilets and/or wash laundry should be eliminated at this time, but the rebate for these systems should remain. The District has not permitted any of these systems for a water credit. Citing concerns about the lack of sufficient data on existing operating systems in Monterey County, as well as the potential for problems related to installation, maintenance, and enforcement, the Committee directed staff to proceed with an amendment to Table 4: High Efficiency Appliance Credits.
RECOMMENDATION: Staff recommends the Board approve Resolution 2022-08 amending Rule 25.5, Table 4 to eliminate the credit for installation of a rainwater/Greywater system to flush toilets or wash laundry.
BACKGROUND: Rule 25.5 sets forth the process for obtaining a Water Use Credit for a Permanent Abandonment of Use. The permitting of Graywater[1] reuse systems to replace the water supply for toilet flushing and washing clothes was approved by the Board in 2019 for Multi-Family Dwellings and for Single Family Dwellings in 2020. However, the realistic application of these systems is more complex than originally thought.
To qualify for a credit, the system would be required to be separate from the Potable plumbing system with the only access to back-up Potable water at the system tanks where it can be metered. Some of the challenges of a Graywater system discussed by the Water Demand Committee and TAC included:
· There is a requirement that the system “capacity” must be designed to meet 100 percent of the annual demand of the plumbed fixture(s), plus three days. In a small-scale setting such as in an Accessory Dwelling Unit or Single-Family Dwelling, this may not be possible depending on the cleaning habits and number of occupant(s). If the system uses rainwater, dry years such as last year might not provide enough water to meet demand.
· The Monterey County Environmental Health Bureau requires a reliable backup water supply to augment the Graywater system, if needed. The resolutions adopted by the Board specify that this should be done by adding a metered auto-fill Potable water inflow valve to the Graywater storage tank, meaning that there is no Potable water available for use at the fixture. However, if the project involves retrofitting an existing building, the Potable plumbing to the fixtures must be permanently removed and replaced with the Graywater system, requiring a plumbing permit and the potential for cross-connection issues.
· Monterey County Environmental Health Bureau must issue a permit for a Graywater treatment system. As part of their permit process, a backflow survey is required. The Graywater plumbing system must be entirely separate from the Potable system to avoid any potential cross-contamination of the Potable supply within the home(s). It makes sense to install a separate Graywater system during construction of a new building where a building inspector can easily oversee the installation. It does not make sense to replumb an entire existing home to accommodate a Graywater system, especially when it must involve permanent removal of plumbing to toilets and clothes washers to meet the District’s definition of “Permanent Abandonment of Use.”
· Cal-Am is requiring that a backflow preventer be installed on any property that has a Graywater system for flushing toilets or washing laundry. Backflow devices require periodic testing and maintenance and are registered with Cal-Am. Water customers must contract with a licensed professional to perform the required tests and make any necessary repairs.
· If the Board were to allow a credit for a Graywater system, there must be meters on the inflow to the treatment system, outflow to the plumbing system, and a meter on the Cal-Am backup fill. The meters need to measure the amount of inflow into the treatment system, the amount of treated water outflow to the toilets/laundry, and the amount of Cal-Am makeup water that might be needed by the system. This information must be submitted to the District annually for a period of five years, which requires resources to contact the property owner and follow up.
· Regular use of Potable makeup water should result in the revocation of a credit and a requirement to permit the water fixtures supplied by the Graywater system at full Capacity.
· District staff is reliant on the Jurisdiction’s Building Inspector to verify that the plumbing systems are separate and that there is no Potable plumbing to the fixtures for which credit is being given.
· Low flow toilets work best with some flow from showers and sinks to boost the removal of waste from the domestic line into the sewer system. By creating a separate system for supplying the toilets, the flush is not augmented with additional Graywater. This could potentially result in backups.
· Graywater systems require maintenance. There is a long-term property owner commitment associated with installation of a Graywater system. Graywater systems make sense in a Multi-Family Dwelling where management is committed to maintenance and operation of the system, but may be inappropriate for single-family dwellings, especially if the originator of the Graywater system sells and a new owner is less committed to its maintenance.
EXHIBIT
14-A Draft Resolution 2022-08, Amending Rule 25.5, Table 4: High Efficiency Appliance Credits to Delete Graywater and Rainwater Reuse Systems
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