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Common Ground Garden Supply and Education Center
“Graywater for Green Gardens”
Sherri Osaka, Landscape Architect Sustainable Landscape Designswww.sustainable-landscape.com
19-April-2014
Water Situation in California
Periodic Droughts in California• 1928-1934• 1976-1977• 1987-1992• 2007-2009• 2012-2014
Increases in Water Rates• San Jose (San Jose Water Company) – 2 tiers
– 0-13 CCF $2.52/ CCF– 13+ CCF $2.77/ CCF– Two tiered rates 1-Jan-2010
• Palo Alto – 2 tiers– 0-6 CCF $4.99/ CCF– 6+ CCF $7.58/ CCF
• Los Altos Hills (Purissima Hills District) – 6 tiers– 0-10 CCF - $2.70/ CCF– Over 200 CCF - $9.95/ CCF
Reservoirs – at 33% Capacity Limit• Almaden -- 34%• Anderson -- 60%• Calero -- 42%• Chesbro — 10%• Coyote – 41%• Guadalupe -- 0%• Lexington – 29%• Stevens Creek – 15%• Uvas — 13%• Vasona – 87%
“Rain falls, but Santa Clara County can't catch it all” by Paul Rogers, SJ Mercury, 11-Feb-2010. “New study shows massive earthquake could causeAnderson Dam to fail” by Paul Rogers , SJ Mercury, 5-Jan-2009
Anderson Reservoirhttp://3dparks.wr.usgs.gov
World-Wide Water Use• United Nations
estimates that 13 gallons (50 litres) required/person/day
• U.S. uses 145 gal./person/day
• Average US household of 4 uses about 200,000 gallons per year
• Queensland, Australia – limited users to 35-40 gal./person/dayOne gallon equals 3.8 litres
Energy Used for Water
15-20% of all energy used in California is water related
(cleaning, moving, heating)The State Water Project
Reservoir high in the Hollywood Hills
Sources of Water
• Conservation (!)• Municipal supply• Graywater• Rainwater harvesting• Reclaimed (recycled) water
Conserve first!
CCF = 100 cubic feet1 CCF = 748 GALLONS OF WATER1 CF = 7.48 GALLONS
Check for leaksRead your water meter
One in every 10 homes has a leak that is wasting at least 90 gallons of water per day.
Water Use in Bay Area Home11,000 square foot lot, pool, low water landscape
• About 120,000 gallons per year
• 90,000 gallons inside house
• 30,000 gallons outside house
0
5,000
10,000
15,000
20,000
25,000
30,000
Dec-Feb
Feb-Apr
Apr-Jun
Jun-Aug
Aug-Oct
Oct-Dec
Average
~ 30-50 percent for outdoor use
Water Use in Bay Area Home11,000 square foot lot, pool, low water landscape
• About 103,000 gallons per year
• 85,000 gallons inside house
• 18,000 gallons outside house
Dec-Feb
Feb-Apr
Apr-Jun
Jun-Aug
Aug-Oct
Oct-Dec
0
5,000
10,000
15,000
20,000
25,000
30,000
35,000
Average Series3Series4Dec-Feb
< 20 percent for outdoor use
Water Requirements
• High water use– Lawns, birches– 16 gallons of water per
square foot per season
• Moderate water– Fruit trees, Alum root– 8 gallons/sf/season
• Low water– Sages, buckwheats– 4 gallons/sf/season
• Very low– Manzanitas, some oaks– No water once
established
Manzanita berries “Little Apples”
Hydrozoning
Efficient Irrigation
Add Organic Amendments to Soil
• Adding compost to 8-13% of soil by weight significantly increases moisture holding capacity
• Decreases the amount of irrigation
Guidelines for Landscaping with Compost-Amended SoilsCity of Redmond, Washington
Lawn Rebates
• Santa Clara Valley Water District, $1/ square foot
• Lawn Be Gone, $0.75/ square foot• Alameda County Water District, $1/ square
foot
19
What is graywater?
Average Indoor Residential Water Use for 12 North American Cities
Adapted from Residential End Uses of Water, by permission. Copyright ©1999, American Water WorksAssociation and Awwa Research Foundation (AwwaRF).
What is graywater?• Water from sinks,
showers, and laundry machine
• No water from kitchen sinks or dishwashers (no food particles)
• No water from toilets (black water)
• No water from laundry if used to clean diapers
• No water containing any harmful chemicals, including bleachWater expert Larry Farwell estimates that extensive graywater recycling
could save more than 16% of the state's residential water use.
April 19, 2009 LA Times article
Where can you use graywater in the landscape?
• On fruit trees and fruiting vines• On above ground vegetables• On ornamental perennials, shrubs,
groundcovers, and lawns
• Not on root vegetables• Not on seasonally planted annuals• Not in the house (except in Texas)
Is Graywater Irrigation safe?
• 2012 Bay Area Study by Graywater Action*• New $450,000 study: "Long Term Effects of
Landscape Irrigation Using Household Graywater“**
• 1992 $500,000 study*** of eight households in Los Angeles. Checked monthly showed no harmful organisms in soil* Graywateraction.org
** Virginia-based Water Environment Research Foundation & Colorado State University***City of Los Angeles, Office of Water Reclamation (CLA,OWR). 1992. “Gray water Pilot Project: Mid-Course Report”. Los Angeles, CA
Graywater Irrigation
• Advantages– Reduces amount of water needed– Reduces maintenance for septic systems– Reduces load on municipal sewer and
waste water treatment systems– Keeps landscapes alive during drought –
mature landscapes valued at $20/ sq. ft.– Little “infrastructure” as opposed to
recycled water
Graywater Irrigation
• Disadvantages– Not for plants that like acidity – unless
pH is balanced– Need to be careful what you put down
the drain—no chlorine, no boron, no salts, no chemicals
– Liquid detergents (enzymes) better than powders (salts)
History of Gray Water
History of Graywater in California
• 1992 first code included in Appendix F of California Plumbing Code (AB 3518)– After drought
• 1997 second code included in Appendix G (AB 313)
Appendix G: Old California Code• Required permit - ~$500 depending
on municipality• Patterned after septic systems• Costly equipment required: tanks,
filters, emitter• California Plumbing Code (CPC)
Appendix G adoption was OPTIONAL
New California Code - Chapter 16A
• Enacted as emergency regulation in August 4, 2009 (during drought!)
• Included in body of California Plumbing code – Chapter 16A -- not optional
• May be prohibited only after public hearing and enactment of Ordinance
New Code Specifies Three Types of Systems
• Non-permitted systems:– Clothes Washer (Laundry to Landscape)
• Permitted Systems– Simple Systems < 250 gallons– Complex Systems > 250 gallons
Clothes Washer System –Laundry to Landscape (L2L)
Clothes Washer System
• No permit required
• Works for slab foundations
• Washer near exterior wall best
Drawing from: Create an Oasis with Greywater by Art Ludwig
Code Requirements for Clothes Washer System1. Notify the enforcing agency, if required2. Direct graywater either to an irrigation or disposal field, or
to the sewer3. Do NOT connect to potable water or pump or affect other
systems (electrical, fire, etc.)4. Contain the water onsite5. Direct to an irrigation or disposal field6. Do not allow water to pond (surface) or runoff7. Discharge under 2 inches of mulch, rock, or other cover8. Minimize contact with humans and pets9. Send water from soiled diapers or other infectious
garments to sewer10.Graywater should not include hazardous chemicals11.Even if you don’t get a permit, you still have to follow
these rules12.Have a maintenance manual
More requirements
• Keep graywater more than three feet away from ground water
• 100 feet for lakes and streams• 1.5’ to 5’ from property lines• 2-5’ from structures• See code for more setbacks
Washers
Front loaders new15-25 gallons per load
Whirlpool top loader circa 199425 to 44 gallons per load
Typical Washer Connection to Sewer
This is what it looks like
Photo from Deva Luna, EarthCare Landscaping
Stacking washer - inside
Air gap at highest point - outside
Photos from Deva Luna, EarthCare Landscaping
Tighten all connections
Photo Deva Luna, EarthCare Landscaping
Decide where the 3-way goes
Photo Deva Luna, EarthCare Landscaping
Use 1” pipe to avoid overtaxing the washer pump
Photo Deva Luna, EarthCare Landscaping
Cut a hole in the exterior wallSeal it with silicone later
Because this is the highest point, put the air gap assembly here.
Run a PVC line out of the house
This is from the 2nd story
Connect the PVC to 1” black poly tubing
Flexible polyethylene irrigation tubing is a better environmental choice.
Toxic Materials - PVC• Produces hydrogen
chloride gas during combustion
• Toxic manufacture and disposal
• Soft PVC contains phthalates
• Toxic glues• See Bill Moyer report
on YouTube, Bluevinyl.org, and Greenpeace
Alternative to PVC
Blu Lock by Hydro-Rain
Let’s go into the garden…
Percolation Test
Dig a hole and prefill it if the soil is dry
Photos Deva Luna, EarthCare Landscaping
Fill your hole with water
Measure how fast it drains. This soil drained 2 ½” per hour.