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WATER DEMAND
COMMITTEE |
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ITEM: |
ACTION ITEM |
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CONSIDER RESOLUTION 2020-01 AMENDING
RULE 25.5, TABLE 4: HIGH EFFICIENCY APPLIANCE CREDITS, TO ALLOW RAINWATER/GRAYWATER
SYSTEMS IN ALL RESIDENTIAL APPLICATIONS |
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Meeting
Date: |
January 16, 2020
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Budgeted: N/A |
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From: |
David J.
Stoldt, |
Program/ |
N/A |
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General
Manager |
Line Item No.: |
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Prepared
By: |
Stephanie Kister |
Cost
Estimate: |
N/A |
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General Counsel Review: N/A |
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Committee Recommendation: 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: On July 15, 2019, the MPWMD Board of Directors adopted Resolution 2019-09, Amending Rule 25.5, Table 4: High Efficiency Appliance Credits for Graywater and Rainwater Reuse Systems. That resolution established a High Efficiency Appliance Credit (Rule 25.5) for the installation of rainwater/Graywater reuse systems for toilet flushing and clothes washing in Multi-Family Dwellings. Staff requests the Water Demand Committee support adoption of Resolution 2020-01 (Exhibit 2-A) for the modification of Rule 25.5, Table 4 to allow the credit in all Residential applications.
BACKGROUND: The 2013 California Plumbing Code allowed for
the reuse of treated rainwater and Graywater for toilet flushing and clothes
washing. The Monterey County Health Department requires a backup water supply
from a reliable source to augment the rainwater/Graywater system. New construction
and remodel projects are best able to incorporate this technology in the
building design to reduce their water demand. This can be done by installing
dual plumbing to the water fixtures or by adding an auto fill valve to the
storage tank.
The District has reviewed the Estimated Annual Water Use Capacity for
installation of a Graywater system to flush toilets in a residential unit. Staff estimates that between 10 and 15
gallons of treated Graywater (depending on the flush volume of the toilet)
would be needed to meet the toilet demands of a household with an average of
2.3 persons. This demand would be easily
offset with Graywater generated from bathing (e.g., one ten-minute
shower). Design of the system would need
to have adequate storage to meet annual demand plus three days to ensure that
the Potable water backup would not be used.
A similar requirement would apply to a rainwater system, which would
require significantly more storage to meet demands during the dry months.
Resolution 2019-09 Amending Rule 25.5, Table 4: High Efficiency Appliance Credits for Graywater and Rainwater Reuse Systems established a 75% reduction in the Water Use Capacity for required for toilets and/or clothes washers supplied by rainwater/Graywater in Multi-Family Dwellings. Requirements to grant the credit include the following:
· The rainwater/Graywater system capacity shall meet 100 percent of projected annual demand plus three days.
· Meters are required on rainwater/Graywater outflow and on the Potable connection to the system with annual reporting to the District.
· A Notice and Deed Restriction Regarding Limitation on Use of Water on a Property will be recorded on the property title.
DISCUSSION: Affordable Graywater recycling technology is available for Single-Family/small scale residential use. New space-efficient products are entering the market place making small scale water recycling easier to do. Rainwater harvesting systems are already readily available for properties of all sizes. Most Single-Family Dwellings have the same capacity to utilize these technologies as Multi-Family Dwellings.
RECOMMENDATION: Staff recommends the Water Demand Committee support adoption of Resolution 2020-01 for the modification of Rule 25.5, Table 4 to allow credit for Residential rainwater/Graywater reuse systems for toilets and Clothes Washers.
EXHIBIT
2-A Draft Resolution No. 2020-01
U:\staff\Board_Committees\WaterDemand\2020\20200116\02\Item-2.docx