The Future of Onsite Water Reuse for Homes

In part 1 and part 2 of this article series, we shared our insights from the past year — uncovering the challenges of water scarcity and drought and the promise of onsite water reuse. In part 3, we’re wrapping up this series with a view to the future and the remaining challenges and opportunities that lie on the path to truly sustainable onsite water reuse.

Earlier, our team learned how communities in the southwest United States were responding to water scarcity and drought — seeking to manage their shrinking water supplies and growing water demands with a system of punishments and rewards like water restrictions or water efficiency credits. In turn, homeowners and the housing industry have been reaching for solutions to balance their water budgets, often sacrificing comfort for compliance.

Unlike previous solutions, onsite reuse can preserve comfort and lifestyle while still providing environmental and financial benefits. However, onsite reuse is still very much in earlier phases of adoption and growth, and its current status seems to be perfectly modeled by the Innovation Adoption Lifecycle — a conceptual framework that describes how new ideas and technologies spread throughout society. First published by Everett Rogers and his collaborators at Iowa State University in 1957, who were then studying agriculture and home economics in rural communities, it has since been applied to many modern technological innovations like computers, the Internet, and smartphones.

Everett Rogers' Innovation Adoption Lifecycle
Everett Rogers' Innovation Adoption Lifecycle

When it comes to household-scale onsite water reuse, we are still somewhere between the Innovators and the Early Adopters. Progress has been split between two approaches: a bottom-up grassroots movement led by individual homeowners, water advocates, and sustainability enthusiasts as well as a series of large industrial projects led by professional engineers and governments.

The Innovators: Greywater’s Grassroots

We’ve already crossed paths with a few homeowners who are experimenting with onsite reuse. Most have systems that simply redirect laundry water toward the shrubs and trees around their homes — a practice known as “laundry-to-landscape.” These systems are usually made from common, off-the-shelf parts and, for a while, they weren’t exactly legal.

Earlier, they made up an informal community of hobbyists sharing basic knowledge via personal blogs and YouTube channels. Over time, a more formal community of experts and practitioners started sharing their best practices, organizing community workshops and training seminars.

What began as a small community of passionate individuals has grown into a larger group of mainstream environmentalists and laypeople concerned about climate change. And whereas building your own greywater system once required a level of technical competence, a comfort with tools, and willingness to drill holes in your wall, now a growing body of specialists are available for hire.

A typical laundry-to-landscape greywater system. Source: Mother Earth News.
A typical laundry-to-landscape greywater system. Source: Mother Earth News.

In addition to teaching greywater system design and construction through hands-on workshops and presentations, these groups began working with policymakers and water districts to develop codes and incentives for greywater reuse. Today, greywater reuse is not only legal but is actually required in many jurisdictions. Because of their efforts, greywater advocates have raised public awareness about the problem of water scarcity and unlocked a larger discussion about sustainable solutions like greywater reuse.

The Early Adopters: Building Momentum with the Green Building Movement

With the growth of the Green Building movement and the rising popularity of certification systems like LEED, EnergyStar, and the Living Building Challenge, developers are taking notice of these solutions and actually starting to implement them. For one, the certifications elevate their brand and green “street cred” among their customer base, who increasingly care about sustainability and environmental issues. Also, as we heard from our own interviews, developers are starting to see how these improvements make financial sense as well.

However, while energy efficiency improvements have been quickly adopted by the building industry, water efficiency has proven to be more challenging. Onsite water treatment systems are much more complicated than rooftop solar panels, so developers have mostly focused on lower-hanging fruits like high-efficiency dishwashers and low-flow showerheads. Early adopters of true onsite water treatment have tended to be wealthy institutional clients, such as corporate campuses and private schools, that can afford the engineering services and permitting fees.

Many of their systems are essentially conventional wastewater treatment plants, scaled down to serve single developments or neighborhoods instead of an entire city. Other systems utilize innovative ecological systems, like constructed wetlands or Living Machines. In either case, these onsite treatment systems are able to produce water that’s safe enough to reuse indoors. However, these approaches are still too large, complex, and costly to be implemented in the suburbs. Onsite reuse technology is indeed advancing, but the technology is far beyond reach for average homeowners who are stuck watering their gardens with laundry water.

The Centralized Alternative

While the Innovators and Early Adopters of decentralized systems are making gradual headway, a number of cities have chosen to focus on centralized solutions. In 2019, the City of Los Angeles announced the applaudable goal of recycling all of the city’s wastewater by 2035. The plan? To treat all of the wastewater at their central Hyperion wastewater treatment plant up to drinking water standards and reintroduce it back into the water supply. It’s technically feasible, but as others have pointed out, it will cost $2 billion and take 16 years to complete.

Hyperion Water Reclamation Plant. Photo by
Hyperion Water Reclamation Plant. Photo by

Unfortunately, most communities do not have that kind of money, or time, on their side. Large-scale capital projects like desalination plants and centralized water recycling, as well as the requisite overhauling of their infrastructure, are huge financial and logistical barriers for the rest of the American Southwest and the world. The solution for them lies in decentralized, onsite water treatment and reuse.

Toward Decentralization

Although state and local mandates for on-site water reuse are beginning to proliferate, they have created a wide variety of (often incompatible) requirements that ward off innovation and increase the barrier to adoption. Jurisdictions need to work together to standardize and streamline their permitting requirements for onsite reuse systems, and as policy continues to develop, water districts need to provide larger rebates to help finance them. Until then, the high retrofit costs prohibit existing homeowners from investing in on-site reuse systems.

Fortunately, California is leading the country in terms of water reuse innovation. With the largest market for water conservation and reuse solutions, their approach to this problem heavily influences the industry and therefore, the rest of the nation. The recently published National Water Reuse Action Plan (2020) describes 37 actions and over 200 implementation milestones and can be adopted right now by any jurisdictions ready to support water reuse.

Crossing the Chasm

In 1991, Geoffrey A. Moore published a revised version of Everett Rogers’ Innovation Adoption Curve, noting a chasm between the Early Adopters of a technology and the Early Majority who follow. The most difficult step for any emerging technology is crossing this chasm, and transitioning from the expectations of the earliest customers to meet the needs of the mainstream market.

The updated Innovation Adoption Curve. Image by Prototypr
The updated Innovation Adoption Curve. Image by Prototypr

Whereas the first Innovators were willing to build their own greywater systems from scratch, and Early Adopters were willing to test expensive, experimental systems that occasionally clogged, the next customer segment — the Early Majority — will be looking for more. In order to serve the remaining 84% of the market along the Innovation Adoption Curve, onsite reuse technology will have to meet those needs.

It was clear from our conversations with various housing developers and home builders that they are attracted to onsite reuse’s ability to increase home values while reducing permitting fees and construction costs. And our conversations with individual homeowners confirmed that they would indeed like to have bigger, greener yards and lower utility fees.

Onsite reuse could enable the comfort and lifestyle they’re looking for while still providing environmental and financial benefits, not to mention freedom from strict water restrictions, and alleviating their “green guilt” for watering their lawns during a drought.

When we spoke to home builders who were using (or have used) onsite reuse systems, we heard similar stories about many former greywater recycling systems that performed well in labs but still failed in real-world settings and were discontinued. The common issue among them was that these systems relied on relatively conventional water treatment processes that merely filtered out larger solids and sterilized the rest with chlorine. These systems invariably clog and require frequent maintenance from homeowners, often falling into disrepair.

While ecological systems show promise in overcoming these challenges, it is clear that robust field testing must be a primary objective for the development of any reuse system. Homebuilders will require simpler, standardized systems that are easy to install and maintain, and homebuyers will be looking for higher performance and better reliability at a lower cost.

The Future of Decentralization

With climate change driving more frequent and severe droughts throughout the American Southwest, the limited availability and high cost of freshwater has led to a growing interest in water conservation and sustainable water reuse. Decentralized solutions like onsite reuse are critical measures for drought resilience and a healthy environment.

Onsite water reuse is still in its early days, but there remains a huge opportunity for growth within the market for new residential construction. However, in order to achieve widespread adoption, the industry needs to provide better technology, cities need to develop better policies, and water agencies need to provide financial incentives for existing homeowners.

LeapFrog Design's water treatment planters for residential onsite water reuse.
LeapFrog Design's water treatment planters for residential onsite water reuse.

In order to overcome the shortcomings of existing mechanical and chemical treatment systems, LeapFrog Design is developing an ecological treatment process that relies on living plants and microorganisms to naturally break down and remove contaminants from household greywater. By forgoing filters and sterilizers, which ultimately clog and fall into disrepair, our ecological system allows for a higher degree of treatment that is safe for reuse in the home or garden. Furthermore, unlike classic large-scale ecological systems like constructed wetlands, our compact, modular design is easy to install and easy to scale. Our goal is to dramatically reduce the cost of onsite ecological water treatment and provide truly sustainable and affordable onsite water reuse for any household.

LeapFrog Design is pioneering sustainable onsite water reuse as a solution against drought and water scarcity. To deepen our understanding of the water reuse market in the US, we interviewed over 130 industry leaders, policy experts, and potential customers.

We asked questions like: How is the water industry addressing drought and water scarcity? How are homeowners and the housing industry responding to rising fees and water restrictions? What are local and state governments doing to encourage conservation and reuse? What technological hurdles need to be overcome in order for onsite water reuse to grow and flourish?

Our conversations and insights point to exciting possibilities for sustainable onsite water reuse in the US and around the world. By sharing what we heard, we hope to spark further conversation and support for non-potable water reuse advancements in the US.

Part 1 studies the challenge of drought and water scarcity and how communities are coping with shrinking supplies and rising demand. Read part 1 here.

Part 2 explores the ways in which homeowners and the housing industry are responding to rising fees and water restrictions, as well as pioneering new approaches to onsite reuse. Read part 2 here.

Part 3 investigates the technological and political barriers for onsite reuse, charting a course for the future.