Learning the Benefits of Diverting Graywater

Reuse of a precious water resource is trending across the country, but it started by necessity in the parched western states.

Learning the Benefits of Diverting Graywater

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The driest January and February on record happened this year in California. With the state facing another year of severe drought, there is more reason for onsite water recycling projects to help stretch the West’s most important resource a little further. 

For more than 20 years, Laura Allen has been recycling water with small-scale projects. She is co-founder of Greywater Action, based in Berkeley, California, and is on a mission to help people to reuse onsite wastewater. She was also called as an expert witness in the lawsuit against an Amish group in Minnesota that resisted county orders to install an onsite system for graywater from the Amish homes. That case went all the way to the U.S. Supreme Court.

Pumper: How has graywater reuse changed since you formed Greywater Action? 

Allen: For one thing, it’s legal in California and many of the Western states. As a result of legalization, and extended water shortages, there’s been a lot more interest from water agencies and municipalities. Before it was very bottom up. People wanted to reuse water — people have always reused water — but there wasn’t the widespread support you see now.  

Pumper: What do California’s rules look like for graywater? 

Allen: There are different tiers of graywater. For subsurface irrigation in California, there’s no treatment needed. Sometimes you filter for functionality so it doesn’t clog emitters, but there’s no actual treatment until the water enters the landscape. Many simple systems use a woodchips basin as a filter in the ground to prevent the soil from clogging. Some local jurisdictions, such as San Francisco, through their public health departments, are requiring treatment for indoor use because there may be contact with people. 

Pumper: What did you reuse when you built your first system in 1999?

Allen: We re-plumbed the shower to lead outside into the landscaping. My 1999 systems are really nothing to emulate. The thing I learned over the years is it really takes time to learn how systems work. Some systems that I thought were great, a year later I changed my mind. 

Pumper: What should people avoid when creating a reuse system? 

Allen: What I found is the simplest way you can meet your needs the better, because every new component or addition is a failure point. The other thing is it really depends on the situation. If you’re growing trees or bushes, or the larger landscapes, those do really well with simple systems. And the simple systems are more affordable, they last longer, they’re easier to install. 

Pumper: About what should someone expect to spend on a graywater system? 

Allen: Laundry to landscape is usually the best place to start, and for that system, the materials are around $200 to $300. It’s usually a one-day installation and doable for a DIYer. To hire somebody to install, the total is about $700, getting up to $2,000. Because washing machines have pumps, you don’t have to change the household plumbing at all. You’re connecting directly to the appliance. Many states don’t require permits because you’re not changing anything about your home, but the state does have to allow graywater reuse. 

You could also spend $20,000 on a graywater system that’s going to be much more advanced. Usually these are only done in high-end new construction. 

Pumper: Your website says you do courses, and are those available nationally? 

Allen: We do courses online, so those are available nationally.

Pumper: Do you charge? 

Allen: In our online school, we have some free introductory classes for anyone who doesn’t know about graywater. And then we have an online class that is more in-depth, and there is a fee. 

Then there’s a design class. That goes step by step through doing a site assessment, soil testing, calculating water flows, calculating plant water requirements, putting it all together, getting permits and getting materials. There’s a weekly coaching session so people can bring their designs and get feedback on them. 

I’m also on the board of COWA (California Onsite Wastewater Association), and we do trainings where people can get continuing education credits through the public health department. 

Pumper: How many places have regulations in place for indoor reuse, for example flushing toilets?

Allen: I don’t know this regulation as well as I know the outdoor. In theory you can do it in a lot of places. In practice there’s more concern because there’s more risk of contact. 

In the California plumbing code there is a category for treated graywater, NSF 350 certified, and then you are allowed to flush toilets with it. You have to get a permit, local approval, but there is a state pathway to do that. Most states that allow graywater do allow both outdoor and indoor use, although in practice it can be much harder to get permitting for the indoor use. 

Pumper: Can you talk about the lodges project near Yosemite National Park? 

Allen: This is one of my favorite examples of appropriate use of graywater. They did this big project at Evergreen Lodge to take the shower water from each of their cabins and direct it through a gravity-flow system, really simple, to irrigate the landscaping right by the cabin. There’s 55 cabins, so these simple systems are irrigating with over a 1 million gallons per year. 

Then they have their commercial laundry, and a simple system wouldn’t work. So they’re pumping, filtering and sending water into the forest to create a hydrated buffer zone for potential fire protection. Then they have their staff showers, and those are also pumped and irrigate the landscape. 

They built a sister lodge after they had the success with Evergreen Lodge, and from the beginning they implemented reuse of all the graywater. They’re also sending the blackwater out to the forest.

Pumper: What was your involvement in the case of the Minnesota Amish? 

Allen: I was contacted by the lawyer for the Amish as an expert witness. In Minnesota, graywater is sewage because there’s no legal separation between the two. These Amish famers have outhouses, like composting toilets, and they don’t have kitchen sinks. They have dry sinks, like a bowl, that they dump out. Their showers and washing machines used a “straight pipe,” basically a big pipe going into the field. This is rural. 

Graywater is allowed in a lot of places in the U.S., so I was called as a witness to give the bigger picture. If it were in Arizona, what they were doing could have been totally legal. I visited the farms and saw their systems, and they redid them before I got there to make it all subsurface. 

Pumper: Can graywater reuse help people with onsite systems? 

Allen: I’ve had people tell me of others who divert their graywater because their onsite systems aren’t doing well. And those people don’t really want to reuse the graywater. They just want to dump it. So we help them do it better, to make sure they’re not causing unanticipated problems. 

Some blackwater people think that keeping graywater out will cause problems in a standard onsite system. But there was a study done in New Zealand where they tested one failing septic and one functional septic. They tested the effluent of both systems, and then they pulled out all the graywater and ran it for a while, and they found it improved the efficiency of the failing system, probably because it increased the retention time.

Pumper: What was it like being an expert witness in the Amish case? 

Allen: I’ve talked with very many skeptical people, but it felt like they wanted to understand. But in a courtroom it’s completely different. They want to win. They don’t want to understand. 

It was very sad to see how the Amish were being treated. And their lives are very respectful, overall, of the environment. One of the most ironic things was in that county, people are legally allowed to pump out septic sludge and spread it on the surface of a farm with no permit. But they can’t put their shower water into the field? It’s like, what’s more dangerous?   


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