Water, Energy and Climate – Why water reuse matters

Water reuse is at the core of Conservation Hydrology.

Nearly twenty percent of California’s electricity and more than thirty percent of non-power plant natural gas is used for water-related purposes: for collection, production, transport, treatment and delivery of water to end users, during the consumption and use of water, and for collection, treatment, and disposal of wastewater [1].  Thus keeping and reusing water in place rather than transporting it long distances conserves both water and energy. This connection between water and energy is referred to as the water-energy nexus.

Updating federal, state, regional and municipal policies to adopt modern onsite water reuse technologies has the potential to save up to 14 million-acre feet per year – that’s equal to 35% of current annual water use in California, and the equivalent of the water used by all of California’s cities in a year. This reduction in demand for new water would also dramatically reduce the amount of energy used and thus significantly reduce the GHGs emitted by California’s water-energy nexus [2].

[1] Francis Spivy-Weber, Vice-Chair, State Water Resources Control Board
[2] Drought-Stricken California Could Save Up to 14 Million Acre-Feet of Water; Enough to Supply All the State’s Cities Annually, Issue Brief June 2014, NRDC and Pacific Institute

Publications

Greywater-ready buildings – model ordinance

This document provides model ordinance language for municipalities to adopt “greywater – ready” building mandates for new construction and is a great resource for forward-thinking architects, plumbers and contractors wishing to integrate simple provisions for greywater into their new building projects.

It details how drainage piping can be plumbed to make it easy, at any future point in time, to install a diverter valve and direct greywater to the garden.  Problems arise, for example, if a second story bathroom does not have separate greywater drain piping coming down the wall to where it can be easily diverted, either low in the wall ( if there is a slab) or in the crawlspace – it can be exorbitantly expensive and disruptive to try to alter drainage piping in the ceiling under a bathroom at a later date. It is equally difficult to access greywater from a groundfloor bathroom if there is a slab and provision has not been made to route the greywater pipes to a point where they can be diverted.  Indeed, planning is best done in advance!

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