Walking into Camp Kerala, guests know right away that it makes a minimal impact on the environment. But with growing numbers of traditional hotels also claiming to be green, how can you tell the truly ecoconscious from the merely “greenwashed”?

For now, there’s no national standard, though Tedd Saunders, president of EcoLogical Solutions, a hospitality-focused consulting firm, is working on developing one. Until then, national organizations like the U.S. Green Building Council (usgbc.org) and Green Seal (available in nine states and at greenseal.org) highlight properties that meet regulatory standards. San Francisco’s Orchard Garden is one of the country’s first hotels to earn the U.S. Green Building Council’s Leadership in Energy and Environmental Design certification. Each of its 86 rooms (from $169 per night; theorchardgardenhotel.com) features a European-style system that allows room lights and air conditioning to be turned on only after a guest has placed her key card in a special holder; this way, electricity automatically shuts off when a guest leaves the room. In addition, the hotel’s furniture is made from sustainably grown maple, the cleaning staff uses chemical-free products and its chefs cook with locally grown ingredients. “Most think that if it’s green, it has to be Birkenstocks,” says Stefan Mühle, the Orchard Garden’s general manager. “But you can have all the amenities you’re accustomed to and still be green.”

Several other accrediting agencies and third-party Web sites exist; Saunders’s favorite is environmentallyfriendlyhotels.com. But purists beware—this resource does not visit properties and relies on management to describe their amenities. If a guest notices a discrepancy, it’s reported on the site. The Green Leaf project (greenhotelsonline.com), out of Canada, is a paid service that North American hotels can join to see just how ecoconscious they are. After managers fill out a checklist, an auditor visits the property to assign a one- to five-leaf rating. Only one five-leaf property exists (Alberta, Canada’s solar-powered Aurum Lodge) and many of the participating properties use their one-leaf rating to see how they can improve.

Of course, travelers should also rely on their own judgment. Saunders says to look for signs of energy and water conservation. The Sofitel Water Tower Chicago (from $245 per night; sofitel.com), which recently broke away from the Green Leaf project, developed its own 65-point environmental plan that includes the use of ozone laundry machines to reduce the use of hot water and detergent. With small changes like that, even the most luxurious hotels are giving new meaning to guilt-free vacations.