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ECO PHX, located at 301 W. Roosevelt Street, is a mixed-use urban infill development of 70 apartment homes and six commercial spaces in downtown Phoenix. This new development uses alternative materials and innovative landscape design solutions. Among those design solutions are two innovations not commonly seen in high-density development projects. The first of these is the use of greywater, generated from residential shower use, as a supplemental irrigation water source. The second is the use of organic mulch, such as shredded wood, in lieu of the commonly used decomposed granite, as ground covering. For this project, the team demonstrated that these two innovations/materials had a measurable qualitative impact on prospective ECO PHX residents’ decision to move to the development and/or to continue living there.

The use of greywater as a supplemental irrigation source in built landscapes is uncommon. To facilitate its use in a public, commercial development such as ECO PHX, the design team invested significant time coordinating with the City of Phoenix development review staff to gain their support for this application. Organic mulch is used as a ground cover at ECO PHX. The material is hypothesized to provide many co-benefits related to air quality and heat, particularly in a desert environment, such as reducing the use of leaf blowers, capturing and sequestering settled dust (and reducing imported fines), and attenuating surface and ambient temperatures. 

HUE was tasked with researching two primary questions and hypotheses related to the ECO PHX project: Would the abundant use of greywater as irrigation have a measurable impact on the soil? Would the landscape that results from the use of these systems and materials be healthier, and might that have a measurable qualitative impact on prospective residents’ decision to move here?

Over the course of the project, HUE researchers collaborated with WERK | urban design to collect, test, and analyze ten soil samples for quality and promotion of soil health to mitigate heat and improve air quality. In addition, the team distributed an opinion survey to assemble data on whether such features influenced prospective residents’ perceptions and desire to live in developments with greywater systems. Final data and findings will guide future investments in dense housing solutions from different sectors (academic, public, private) to further support the use of innovative options to improve local livability in urban developments.


WERK | urban design

Sustainable Cities Network


ECO PHX presentation

Final Report



Healthy Urban Environments