The intent of Water Efficiency Credit 1.2 is "to limit or eliminate the use of potable water for landscape irrigation."
Colorado has some of the most stringent water rights laws in the country. The site of our project, the University of Colorado, Boulder Campus draws 100% of its landscape irrigation water from Anderson Ditch, a ditch which is fed by rain and snow melt and Boulder Creek, which is primarily used for agricultural purposes. Our project, the Wolf Law Building, on the University of Colorado, Boulder Campus will be landscaped with xeric plantings; irrigated with high efficiency hardware informed by two weather stations; and irrigated entirely with Anderson Ditch (non-potable) water, which the University owns water rights to. Our question is: Does the USGBC agree that use of water from the Anderson Ditch qualifies to "limit or eliminate the use of potable water for landscape irrigation"?
According to the nationally renowned Water Rights Lawyers who will be occupying the building, the short answer is: Yes, Anderson Ditch is a non-potable water source according to State of Colorado Law. In addition, we have concluded that Anderson Ditch is a non-potable water source according the USGBC's stated definitions.
"X According to the USGBC, "potable water is water that is suitable for drinking and is supplied from wells or municipal water systems." (LEED Reference Guide, page 89). Anderson ditch water is not suitable for drinking nor is it supplied from a well or a municipal water system. It is also stated on page 98 of the LEED Reference Guide, "potable water is defined as water that meets drinking water quality standards and is approved for human consumption by the state or local authorities." Anderson Ditch water does not meet drinking water quality standards.
"X Per the WE credit 1.2 CIR (1/20/2004), "The term 'potable water' is used by the USGBC to differentiate 'recycled graywater' (lavatory or shower water) and 'harvested rainwater' from 'receiving waters' (rivers, lakes, aquifers)." Although the Anderson Ditch does not fall clearly into any of these three categories, it is not a river, lake, or aquifer. It is also stated in this CIR that " 'industrial water' delivered by the municipality, which is not treated, is nonetheless drawn from a source (Tennessee River) that provides the municipality access to water that is treatable and ultimately potable," therefore using any municipally supplied water would not satisfy the credit requirements. (Id.) Anderson Ditch is not municipally supplied.
In Colorado, most water is reused several times before it leaves the State, so river water, rainwater, and graywater, are equally "treatable and ultimately potable." Harvesting rainwater in Colorado is the legal equivalent of diverting water from a natural body of water. Under Colorado's prior appropriation doctrine, harvested rainwater cannot be put to a beneficial use (such as irrigation) without a plan for augmentation that replaces the depletions associated with that diversion. Furthermore, the use of graywater in Colorado requires treatment by an individual sewage disposal system and requires CDPHE permitting and monitoring.
In conclusion, we believe that the use of 100% Anderson Ditch Water for our project's (extremely water efficient) irrigation satisfies the intent of WEc1.2 and should earn LEED credit. Please verify.
The credit requirements specifically state "captured rain or recycled site water" as water sources applicable to this credit. Its intent, as noted in CIR ruling 9/19/05, is to promote the use of site-sourced reclaimed water for irrigation (if irrigation is needed) to achieve site self-sufficiency and reduce the demand for water that would otherwise be used elsewhere.
In Colorado, water supply for most irrigation ditches is taken from a watershed, river, or lake, diverted into a canal or ditch and delivered to downstream users as irrigation water or supplemental irrigation water. In most cases, if that water is not diverted into the irrigation ditch, it can be used for some other purpose, including potable water. Typically, a share of the ditch company entitles the shareholder to delivery of some amount of water for irrigation purposes. However, that share of the ditch can be sold to the City or a water district which will enable them to divert the share entitlement to the City or District potable water treatment plant. Typically, a developer or someone needing a source of potable water, will buy shares in the ditch, turn those shares over to the City or District and receive credit for potable water taps. If these conditions apply to the Anderson Ditch, its water could be considered potable and therefore could not contribute to the achievement of this credit.
WE TAG has proposed a modification to this credit for LEED-NC version 2.2 that will allow renovated wastewater provided by a municipal agency to be used for WE Credit 1. For v2.1, the water from the ditch can be applied towards achieving WE Credit 2 and a related innovation credit. Applicable Internationally.
Related Addenda (Corrections & Interpretations)