This piece, cross-posted from Sightline, is part of the research project Making Sustainability Legal.

Call me a dreamer. I want to flush with rainwater. Rain barrels already anchor my downspouts. I want to hitch them to my toilet tank. It would save me money and leave my city’s drinking water for better uses.

Yet so far local plumbing rules aren’t helping me, or thousands of others, make the rain-barrel connection. It’s not so much that rules prohibit it, but that even local authorities do not really understand what the rules mean. A little clarification — and publicity — would go a long way.

Already, outside my house in Seattle’s Ballard neighborhood, I’ve managed to irrigate my Victory Garden all summer from nothing but the 500 gallons of rain I collect in 10 barrels. During the other three seasons, though, the garden doesn’t need extra moisture, so my barrels sit unused and, often, full to the brim.

So I’m flushing my toilet with pure, treated drinking water that’s piped scores of miles from the Cascades while I’ve got hundreds of gallons of free, naturally delivered, and naturally replenished rain stockpiled just outside my bathroom wall. Perhaps you now understand the intensity of my dream? A Rain Water Toilet Flush system (RWTF)!

I’m a perfect candidate: I live in a 1920 single-floor, 800-square-foot fisherman’s shack, so everything is down low to the ground and close together. My girlfriend and I have been doing our best to conserve water. Our consumption this past winter, for example, was half of what we used a year earlier. The U.S. average is 70 gallons per person per day, according to the Environmental Protection Agency. According to Seattle Public Utilities, we got our average daily water consumption down to 25 gallons apiece. By connecting our rain barrels to the toilets, we could reduce our water use by another nine gallons a day (six flushes a day times 1.6 gallons per flush). Also, we could stop being one of those stinky “if it’s yellow, let it mellow” households!

A toilet can account for anywhere from 27 percent (older toilets) to 8 percent (low-flow toilets) of household water use. There are over 130,000 single-family homes in my city alone. If only 10 percent of these homes used such a setup to reduce their municipal water use by a quarter, it would save more than 645,000 gallons of water a day, or 19 million gallons a month. Extend that math across America, and the savings multiply.

Back to my personal challenge: I have a single toilet situated just a few feet above ground level. Connecting it to my rain barrels should be easy, right?

Wrong.

Unfortunately, it’s not as simple as drilling a hole through the wall and attaching the toilet to the barrel (aka “Experiment No. 1” — don’t tell the plumbing inspector, but I may have already tried that). It involves principles of hydro- and seismic engineering. For a gravity-fed system, you need height. Water weighs 8.3 pounds a gallon. A full 50-gallon barrel weighs more than 400 pounds. Hoisting it to an adequate height, in earthquake country, you need some reinforced structure. Not too complicated, but definitely not simple.

And then there’s the permitting. Both Washington State and Seattle allow rainwater catchment systems for indoor, non-potable use, but finding out how it’s done and what the permits are sure ain’t easy. Trying to do so led me on a three-year wild goose chase that finally, I hope, is coming to a fruitful conclusion.

For answers, I looked to Portland, where examples of RWTF systems are almost as common as microbrews and bicycles. The Portland Bureau of Planning and Sustainability website includes some interesting and practical examples of single-family RWTF systems. A call to the office put me in touch with Valerie Garrett, who staffs the Green Hotline. After I told her of my quest, she referred me to Pat Lando, a local contractor who has been designing and installing rainwater systems for 10 years.

Lando clarified everything: Early on, he was stymied by the high costs of household rainwater systems, so he developed his own kit. He hesitated to give estimates, but when pressed, he suggested $2,600 for an installed, effective system. The main costs are the cisterns and installation, so if you’re handy it could be much cheaper. (I later found a plumber in Seattle who said the materials cost between $1,700 and $2,400.)

Not only that, to maximize savings and return in investment, I learned that I could go beyond a RWTF system, to a “Rainwater for Non-potable Household Use” (RNHU) system. That little three-letter switch in acronyms would allow me to use rainwater not only for the largest consumer of indoor water (the john) but also for the second-largest: the washing machine! Doing so would cut household water use not by 27 percent, but by half!

There was good news, too, on the plumbing codes: Both Oregon and Washington (and many other states around the country) use the International Built Plumbing Code, so I could use an Oregon design — if only I could get the proper permissions.

For these, I went to Larry Fay of the King County Department of Public Health, who explained that for $210, I could get a permit for a standard plumbing fixture and three outlets to use rain water. (I would only use two outlets: toilet and washing machine.) The price includes review. Once my plan passes review, I can legally start tapping my rain barrels for indoor use. Or I can get a bigger storage unit, a cistern for indoor use. Plumbing authorities’ main concern is that your rainwater system doesn’t cross-connect with the municipal lines, allowing contamination of city drinking water.

But there’s another key point: Only in 2009 did the Washington Department of Ecology allow rainwater catchment systems at all; before that, capturing and storing rainwater violated water resource law. This is a common occurrence in Western states — so before you go looking for that magical connection, make sure your local and state authorities allow it!

That said, some areas are going even further than the RNHU. King County, I’m told, will soon allow rainwater catchment systems to provide household potable water. In my town, at least, the “someday” when we’ll make the rain-barrel connection is drawing closer all the time, for the regulations, the dreamers, and me.

Cross-posted from Sightline Daily.

Tight budgets and the internet have given rise to the hottest new thing in travel accommodations: spare bedrooms.

Web-based company Airbnb has received a lot of press recently for its for-profit service that matches travelers with empty bedrooms, such as mine, in Seattle. Airbnb and other companies that create a market for guest rooms could fundamentally change the hotel industry, boost income for thousands of homeowners, and slash the ecological footprint of travel.

That is, unless the emerging eBay of bedrooms is strangled by a thicket of rules and regulations that currently govern the operation of hotels.

Last May, New York City enacted a law “banning renting out Class A residential spaces — apartments intended only as permanent, rather than transient residences — for less than 30 days,” according to the real-estate magazine The Real Deal. “The move was prompted, in large part, by complaints from those living next to apartments rented on the website [Airbnb], as well as from the Hotel Association of New York City, a trade group that was concerned about short-term rentals eating into the city’s hospitality business.”

The company is still going strong in New York City, with growth clocking in at 35 percent per month since September 2010. Still, the law casts a legal shadow, if not a legal net, over a growing slice of what’s come to be called the “sharing economy.”

This kerfuffle in New York has spotlighted Airbnb’s vulnerability, and while no other jurisdictions have yet clamped down as publicly as New York, who knows what hotel-industry counterattack is in the works.

Think it couldn’t happen? The situation is eerily similar to what happened to Zipcar in the state of Washington in 2007. Zipcar was then the rising star du jour of web-based collaborative consumption enterprises. Out of the blue, the Washington Department of Revenue ruled that Zipcar had to pay the state’s rental car tax, which adds 10 percent to the existing state sales tax.

The department did this because the rental car companies had been quietly threatening to make a giant stink about unequal treatment. Zipcar and car-sharing advocates did not hear of the tax hike until it was too late to stop it. They were caught flat-footed. Since then, Washingtonian car-sharers have never been able to roll back the change, despite considerable effort. Politically, undoing changes is like putting Humpty Dumpty back together again.

Proponents of the fledgling industry of in-home hoteling would do well to anticipate the attacks that the hotel industry will undoubtedly unleash, and may be plotting already. Otherwise, they’ll end up blindsided.

After all, the whole enterprise is still in its infancy. In greater Seattle, for example, about 700 different lodgings are now available on a typical night. That counts both Airbnb and Couchsurfing.org, the older, free counterpart used by backpack travelers worldwide. (If Airbnb is the eBay of guest rooms, Couchsurfing is the Craigslist.) Taken together, they amount to just 2 percent of the 34,459 hotel rooms in the greater Seattle area.

Still, the rapid growth of in-home accommodations could take a big bite out of hotels’ business. That’s especially true when you consider that much of North America’s existing housing stock was designed for larger families than are common today. One study by Urban Futures in Vancouver, British Columbia, estimated that 29 percent of all homes had more bedrooms than people in them. That’s more than 220,000 empty bedrooms in that city alone. Multiply that across the landscape and you’ve got a massive untapped reservoir of accommodations, already built, painted, furnished, heated (and sometimes cooled), and provided with bathroom and kitchen access.

Of course, sharing your guest room or your home with perfect strangers is not without its risks. A few bad apples got through Airbnb’s screening before the company tightened up its systems. But channeling travel growth into existing homes rather than new hotels would bring big environmental benefits, as Finnish think tank low2no.org argued in an analysis of the carbon footprint of hotels.

Yet this green, affordable, and sociable form of housing for travelers is vulnerable to cries of unequal treatment from big business. Conventional hotels are regulated in special ways under land-use laws (their locations and sizes), building codes (fire safety, structural integrity, handicap access), health codes (especially if they have restaurants), and tax laws (most jurisdictions have special taxes on hotel stays, for example).

The spare-bedroom market, however, flies under the radar of most such laws at present. Exempting it from hotel-specific regulations makes good sense. Social evaluation tools on collaborative consumption sites such as Airbnb (think of the seller and buyer rating systems on eBay) allow a degree of transparency and accountability unheard of in prior times, which obviates the need for as much regulation and public enforcement.

Besides, in the new era of straitened economics, expensive energy, and the imperative of moving beyond carbon, we should be encouraging, not constraining, fuller sharing of existing assets, whether cars or bedrooms. Especially when it boosts income for homeowners.

Including me! If you’re coming to Seattle …