Cool Davis partner Eco Assistant is hosting a hands-on installation Greywater Workshop in West Davis on Thursday, September 7 (6:30–9:30pm), Friday, September 8 (9:30am–4:30pm), and Saturday, September 9 (9:30am–1:30pm).

The two-day workshop consists of three sessions (designed to beat the heat!) featuring instruction on code and methods for the two basic greywater systems and hands-on education and installation taught by Greywater Action Certified instructors Leslie Crenna and Kent Thompson.

What is greywater?

In California, greywater is defined as water collected from washing machines, sinks (excluding the kitchen sink), showers, and bathtubs that can be used for landscape irrigation. Using greywater to supplement or replace traditional irrigation systems will likely help you reduce your household water usage, especially in summer, by reducing your need to use potable water for outdoor irrigation.

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Greywater Action certified instructor Leslie Crenna presents at the recent Greywater Showcase held at the Davis Senior Center August 4, 2017. Photo credit Johan Verink.

Certified instructors

Instructors Leslie Crenna and Kent Thompson were both trained and certified by Laura Allen of Greywater Action who has decades of experience designing, installing, and consulting on state level code.

Kent is a Landscape Contractor but neither instructor is a plumber. Greywater has been a tricky situation for those providing the service because those two trades are generally not practiced by the same individual.

Both instructors are also very familiar with state code and how to follow it to create a safe and code compliant system. The permit for the system being installed at the workshop has been approved by the City of Davis.

Leslie has three years of greywater experience and Kent six. Leslie also participated in the EPA Water Sense-certified QWEL (Qualified Water Efficient Landscaper) Greywater training module sponsored by the Sonoma Marin Saving Water Partnership this past February.

Greywater workshop details

September 7 (6:30–9:30pm): Instruction on the two basic greywater systems, Branched Drain and Laundry to Landscape.

September 8 (9:30am–4:30pm): Hands-on installation of two Branched Drain systems in the morning and further instruction in the evening.

September 9 (9:30am–1:30pm): Hands-on installation of Laundry to Landscape system.

The workshop will host installation at a new build site, focusing on the outside portion of installation.

The interior portions of the system have already been installed under the supervision of a General Contractor, so workshop participants will be inspecting the interior and finishing the exterior portions of the systems.

The instruction will cover information about permits, design, calculations, soil testing, depth of discharge, greywater discharge, and more.

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Greywater Action certified instructor Kent Thompson presents at the recent Greywater Showcase held at the Davis Senior Center August 4, 2017. Photo credit Johan Verink.

More on greywater

The recent Cool Davis and Water Wise Davis sponsored Greywater Showcase (and City of Davis supported) and City of Davis website have more information about greywater for interested residents.

If you have any more specific questions, please email Leslie directly at or visit the EcoAssistant website.


Register today! The workshop costs $93, but you can save three dollars when registering with a check by mail.

Eco Assistant provides assistance with personal sustainability goals through consulting, workshops, installations, and educational services and is a Green Business Partner with the City of Davis.

Branched drain greywater installers
Installers working on a branched drain system measure the run from one splitter to another. Courtesy photo.