The Guild Report:  
Greywater and More!
April 2012 
In This Issue
Point of View
Graywater Case Study
Graywater Resources

Point of View  
With Employee Owner
Paul Thunstrom
 Paul Thunstrom


"What I appreciate about being at Gardeners' Guild is the collaborative approach to everything we do. Also - many decisions are made on a consensus basis.  

This makes me feel more involved - and it's one of the reasons  I am so loyal to the company."


Paul is our Enhancement Division Manager.  He has been with Gardeners' Guild since 2000.      He is a graduate of UC Berkeley's Landscape Architecture program. He has also completed UC Berkeley's LEED for Landscape Architecture's program and is currently involved in the east bay project discussed in this month's newsletter.  









Using greywater or graywater (either spelling is correct) to irrigate plants has become an increasingly popular topic of discussion throughout the world. My recent google inquiry yielded over 3,000,000 hits!  


What is graywater exactly?  It is most household water including bathroom sinks, baths, showers and washing machines; with the exception of water from toilets and kitchen sinks.  About 50-80% of household water is graywater.


There are many benefits to graywater recycling for irrigation.  The main one of course, is that it can cut water use significantly.  It will reduce strain on septic systems and municipal water treatment facilities. Graywater recycling can also help promote plant growth in areas where plants might not normally receive sufficient water.


There are also some pros and cons to this option.  This month we cover graywater and in particular, a case study of one of our projects that consists of two different systems designed to re-use water, and one to collect rainwater.  


Please let us know if you have any experiences with graywater.  We'd love to hear from you.


All the best,
Suzanne Harris

A Case Study

An average four person household sends approximately 38,000 gallons of water down the drain each year from their bathrooms and washing machines.  We don't know what the future holds for our water supply. Therefore, graywater systems are important alternatives.


The elements of a system:

  • Pipes that transport the greywater from inside to outside.
  • Distribution plumbing: pipes that transport the greywater from just outside to the locations throughout landscape
  • Surge tank and filter: optional - makes distribution easier, but is more expensive
  • Receiving landscape: soil, roots; plants that contain, cover and purify the greywater.

A residential client of ours in the east bay has taken on an ambitious renovation of their large home and landscape.  The owners' vision of their house is that it be a demonstration of sustainability for neighbors and friends. The project is expected to achieve LEED Platinum status.  Some of their extra points are a result of three individual systems:


1.  Graywater

All the water from bathroom sinks, tubs and showers go through a filtration system, into a collection area, then is diverted into the landscape.  Their plan is to generate 120 gallons of water per day.
Note: there are flush requirements, meaning that there is a limit to how much water the system can hold before it needs to be flushed into the landscape or the sewer system. 


2. Laundry Water System

Separate from the graywater from bathroom sinks and showers, this water also is simply drained into the landscape.  Plants are specially selected to tolerate a high level of phosphates (from the soap).  

A consideration about this system: the soaps used in the washer.  Experts recommend not using liquid fabric softener or harsh detergents and to use low sodium products.  The most damaging chemicals for plants are boron, borax and bleach.     


3. Rain Collection/Harvesting 

The roof is composed of laminated solar panels. The plan is for rain to collect on the roof; pass through grates (which are a sort of filtration system) and then down to 15,000 gallon tanks.  Water will be used in showers and sinks.  

Note: a roof for a 1,000 square foot house can collect around 600 gallons per one inch of rain!  


Graywater systems do require maintenance and in certain situations they are not the most sustainable approach.  Here is a list of considerations:


  • They may not be allowed in certain municipalities
  • A permit is required unless it is SFPUC "laundry to landscape" program.
  • If your soil is not permeable enough, the recycling of greywater may not be feasible or could be expensive to implement
  • If your garden area is too small it may not be worth the investment.
  • If the graywater system requires more maintenance than a properly functioning  septic or sewer system it may be more sustainable to not pursue this option. 




Graywater Resources

Check out these links for more information:
SFPUC - Laundry to Landscape Program- they offer a $95 rebate on their graywater kit