We’re running out of water. The Ganges, Yellow, Yangtze, Indus, Brahmaputra, and Mekong rivers collectively irrigate the food crops for nearly a billion people. The glaciers that have fed them for eons are rapidly melting. Within my son’s lifetime, if not my own, these rivers are projected to be seasonally dry.

A similar issue affects rivers fed by snowmelt in California, America’s fruit basket. The Ogallala aquifer supplies 30% of the groundwater used for irrigation in the United States. But it is “fossil water” from the last ice age, and it’s being extracted at 100 times the replacement rate.

Even places that don’t have water-quantity issues have water-quality issues or are connected umbilically to places that have both. Meanwhile, we’re living fat on the drawdown of this resource. And water isn’t the only natural capital we’re squandering. In our lifetimes, we will see not only peak oil and water, but also peak just about everything else, including clean air and topsoil. To deal with these emergent risks, we must learn to live on fewer resources, much better utilized.

Why throw resources down the drain?

First and most important, we need to build smaller and for the long haul. A small home well crafted to last for centuries uses a fraction of the resources of a big house designed for a one-act play: the sale. And because the most concentrated flow of money, materials, energy, nutrients, and water is through our kitchens and baths, we should start there. Smaller kitchens and fewer bathrooms consume fewer resources in their construction, maintenance, heating, cooling, and lighting. Would this really be such a sacrifice? People who live on yachts are happy with bathrooms barely bigger than a phone booth and galleys in which you can reach everything without taking a step. Good design matters more than size.

Size and number aside, what makes our kitchens and bathrooms so wasteful are the resources that we literally throw down the drain (or into the garbage). The nutrients and water flowing through a typical kitchen and bath are enough to fertilize a densely planted suburban lot and to irrigate a quarter of it. But instead of banking this natural capital in the soil outside our homes, we pollute waterways with it—and we spend money and even more resources to do so.

We need to rethink the flow of these resources through our homes. It is entirely possible to develop systems that yield a higher quality of life than the average American currently enjoys, with one- or two-tenths of the resource use. How might a kitchen and bath work that fulfill this goal?

Use less water

The first question about any human habitation is: Where does the water come from? In Santa Barbara, Calif. (where I’m writing this), our municipal water supply comes from fairly clean surface- and ground-water, but for various reasons, it makes sense to back this up with rooftop-harvested rainwater.

My ideal house would have a pair of attractive, urn-shaped ferrocement cisterns sitting under the lowest gutter. Ozone-purified rain from the roof fills them several times over, supplying enough water to meet a family’s needs in the rainy season. (Drinking water, by the way, could still come from the city.)

In the dry season, the house switches to city water, but the cisterns remain for emergency needs after an earthquake or during a wildfire. In hot weather, one cistern even serves as a cold plunge, so residents can cool off without the cost and complexity of a swimming pool.

“We need to get some of the efficiency motivated by carrying water, without carrying it.”

Worldwide, people with running water use an average of 100 gallons per day to accomplish the same tasks that people who carry water achieve with 10 gallons. We need to get some of the efficiency motivated by carrying water, without carrying it. Anything that increases awareness of consumption and makes conservation easy is a step in this direction. My ideal kitchen would have a water meter in the backsplash behind the kitchen sink (along with remote electricity and gas meters), which places resource-use information where it can be acted on (like the mpg dashboard readout on newer cars).

Foot-actuated valves in the kitchen and bathroom sinks let people start and stop the flow while their hands are busy, lowering water use and keeping chicken slime and other pathogens off the faucets. Over the kitchen sink, an attractive Tuscan-style dish rack stores and air-dries dishes so efficiently that there is no point in having a dishwasher. A capped chute by the sink leads to a compost bin outside.

A third tap at the kitchen sink, with a reverse-osmosis filter, provides tasty drinking water, eliminating the need for bottled water and its associated costs to the environment.

Water flows from solar panels on the roof to highly efficient bathroom fixtures, including a bathing chamber redesigned for comfort and efficiency. Bathers need only a small amount of water to get clean, but typically use a lot of hot water to keep from getting cold. Meanwhile, most of the energy ends up warming drainpipes and fogging windows. The redesigned bathing chamber is highly insulated and designed to reduce heat loss by convection, conduction, and radiation.

Bank nutrients in the soil

In my ideal house, there is no sewer connection. Water cascades between uses, starting inside with those requiring the clearest water and ending outside where topsoil organisms and plant roots filter pathogens and feed on nutrients. The drain beneath the kitchen’s filtered third tap flows to a water feature before heading outside to help irrigate vegetables. Discharge from the washing machine directly irrigates fruit trees, which yield shade and privacy in addition to fruit.

Other gray water (from sinks and showers) discharges into mulch-filled basins before irrigating fruit and ornamental trees. Any excess irrigation recharges the groundwater.

“The most ecological solution is always the most economical, too.”

Black water (from the toilet) flows to a green septic system, which disseminates effluent in a controlled way to fruit-tree roots. If the homeowners are really committed, I would substitute a composting toilet and eliminate the need for a septic system to reduce household water use further.

A house in which the water, waste-water, energy-, and food-production systems are designed simply and synergistically would cost less than conventional practice, especially over time, and even more so when external costs are accounted for. Waste is expensive. If your accounting is complete, the most ecological solution is always the most economical, too.

Context is king

Those accustomed to uniform solutions may be quick to point out how these designs would not apply in other situations. Correct. None of these solutions are applicable across the board. We need a range of solutions that are matched to their contexts, using common sense. Standardized solutions (flush toilets, for instance) are more idiot-proof, but they’re wasteful and dangerously unsustainable. Much of what makes designs ecological is careful attunement to the resources and limitations of the site and the users.

In Maine, for example, a house could have an attached passive-solar greenhouse. The cistern would be in the greenhouse to keep it and the greenhouse from freezing, and also to keep the greenhouse from frying in summer. Irrigated with warm gray water, soil organisms in a greenhouse can treat water year-round. Waste wood from pruning trees can heat a wood-burning bathtub in the greenhouse. Soak for hours in the tub, and then do laundry with the water before irrigating year-round greens. After percolating through greenhouse beds, the purified water can be released to natural waters or used for raising fish.

The greenhouse would likely pay for itself through reduced home-heating costs. It might also prove to be the most popular room in the house.

Legalize sustainability

Why aren’t we all getting healthy on fruit from Eden-like gray-water gardens? Well, we’re not allowed, at least in most parts of the United States. Even as all of humanity’s life-support systems are threatened, the more ecologically you live, the more illegal it is. In Santa Barbara, 20,000-sq.-ft. mansions are approved routinely, but living in a yurt is illegal. You can build an entirely passive-solar and wood-heated house, but the law also requires a fossil-fueled central-heating system. If a sewer passes the house, you must hook up to it, and pay for the privilege.

Our plumbing codes evolved to protect us from 19th-century risks. Certainly, we still need plumbing that won’t spread cholera. But while codes work hard to reduce the risk of disease from minute to infinitesimal, they miss the big picture. If we do not change our built environment to address global warming, aquifer depletion, and groundwater contamination, cholera will seem welcome by comparison.

A good start would be for all states to emulate Arizona’s three-tiered approach to regulating gray water. No permit application is required for systems under 400 gallons per day (GPD) that meet a list of reasonable requirements. Systems over 400 GPD, or that don’t meet the requirements, need a permit. The third-tier systems, over 3000 GPD, are considered on an individual basis.

But gray-water approval is  just one component. We also need experimental permits that allow people to develop unhindered the kind of “lifeboat” systems that I’ve described here. We need to encourage research and gain more experience with resource-efficient systems now.

Although I have focused here on our dwindling supply of water, the real problem runs deeper. It’s a culture in which the looting of natural capital from ours and future generations is institutionalized, encouraged, even legally mandated. For an orderly transition to a post-peak world, we need to take actions that increase stores of groundwater, fertile soil, clean air, trees, and more. Our lifestyles have to change, but I’m confident that we can still enjoy our lives.