Starting January 2010 the changes to the California Building Code made it easier for homeowners to install a laundry to landscape graywater system — no permit required for this simple system. Using the laundry water from the washing machine to irrigate your landscape cuts down on your water demand during the summer. Makes sense, right? I won’t go into the details of graywater requirements, benefits in this post. If you’re interested you can read about in these links:
What is Graywater
City of Santa Cruz Requirements for Installation of Graywater Irrigation Systems
Guide to Conserving Water Through Rainwater Harvesting and Graywater Reuse for Outdoor Use
What I do want to share is my experience of learning about a simple graywater system installation in a Do It Yourself workshop. Last Saturday I attended a day-long graywater workshop in Santa Cruz led by LeAnne Ravinale of Laundry to Landscape and Ken Foster of Terra Nova Ecological Landscaping. About 10 people participated in this hands-on workshop where we learned the basic concepts in an hour-long classroom presentation then went outside to do the installation. I liked this approach because it builds the knowledge in the community and it’s cost-effective for the homeowner.
The homeowner wanted to re-use the laundry water to irrigate the rose plants. Here is a rough sketch and an overview of what we did.
1. At the washing machine, we connected a 3-way valve to enable the homeowner to direct the laundry water to either to the landscape or to the sewer.
2. Outside the house the we fastened the PE tubing to the wall and ran the trunk line to the yard.
3. T-connectors were installed to connect the branch lines leading to the rose plants from the main trunk line.
4. We dug around the plants to make a “C” shaped moat around the plants.
5. Plastic potting containers were cut and placed in the ground.
6. We tested the system using water from the hose bib and adjusted the volume valves at the end of the branch line. Then we mulched the area nicely.
1. At the Washing Machine
A hole was cut into the wall of the laundry room ahead of time.
A piece of plywood with cutout for the 3-way valve was fastened to the wall at the stud.
The workshop participants were 60% women and we all took turns to use power tools and such to install the 3-way valve and plumbing at the washing machine. So it’s light construction work that most people can do.
The bottom connection is to the washing machine
When the yellow handle points down the laundry discharge goes to the sewer on the right side.
When the yellow handle is horizontal (pointing right) the laundry discharge goes to the landscape.
Why should the owners care? During the winter rain the landscape does not need water so laundry water can go to the sewer. Also if you’re washing materials containing bacteria like diapers you need to send the laundry water to the sewer.
2. Outside the House
The 1-inch polyethylene (PE) tube was fastened against the exterior wall.
The 1″ PE tube ran down the wall, across the walkway then ran along the fence perimeter.
We used about 80 feet of this 1″ PE tube as the trunk line. This was fastened to the fence and also staked down into the ground with a staple.
The walkway was covered later to protect the PE tube and prevent it from becoming a tripping hazard.
At specified placed the 1″ trunk line was cut and the T-connector was attached.
Note that the bottom of the T is a smaller diameter where 1/2″ PE tube (branch line) can be attached.
See the completed connection of the branch line near the rose.
One of the requirements of graywater irrigation is that the discharge water needs to be at least 18″ away from the fence.
4. Digging Around Plants
Note that the hole we dug is not directly at the root of the rose plant. It’s deep enough to bury a quart sized plastic potting container.
It’s a bit hard to see in this photo, but we dug a “C” shaped moat around the rose plant. The moat and the larger hole will be filled with mulch. When water is discharged at the end of the branch line the mulch will absorb and convey the water .
5. Cutting Up Potting Containers
Here you can see the a circle cut in the middle of quart-sized plastic potting container so the branch line can be inserted.
The “bottom” of the container will be the top cover that can flap open so that the owners can check the end points for maintenance.
The plastic potting container is placed in the hole we dug.
6. Testing and Mulching
When all branch lines were installed in their respective places the system was tested.
We attached the garden hose to the connector on the trunk line and ran water through the system to see how much water was coming out at each branch.
Flow restrictor valves were used at the end of branch lines to control the volume of the water discharged at each end point. Without this all the water would pool at the first few branches and nothing would get to the end of the line.
Here you can barely see the trickle of water coming out of the valve.
Note that the branch line is “hanging” from the side of the potting container and the valve doesn’t touch the bottom.
See how the “flap” is pulled back so that you can see the valve at the end of the branch.
Mulch is spread around the area outside of the potting container.
Ornamental stepping stone will be placed on top of the “flap” so that the homeowner will know where the end points are.
That’s it! It’s a simple system that takes a little bit of labor.
The instructor, LeAnne, visited the homeowner the day after the installation to do a test with the washing machine. She mentioned they found some leaks and things had to be tightened but otherwise the system worked and the homeowner was happy.
I heard that the local ProBuild Store on River Street has the graywater stuff organized neatly in one area so I checked it out. Sure enough all the materials we used were displayed at the end of the aisle. You can see from these photos that the materials are not expensive to do a simple installation.