Visitor services are limited inside the canyon, with Phantom Ranch  the only purveyor of such creature comforts as lemonade and postcards. Cell phone service is unlikely, and only a few emergency phones are available at ranger stations and resthouses. River guides carry satellite phones.
The biggest concern for hikers and backpackers, however, is water. Inner canyon water pipes are shut off in the off-season, and verifying water sources before you hike is essential.
All white-water rafting trips  through Grand Canyon put in at Lees Ferry, outside Grand Canyon National Park in Glen Canyon National Recreation Area, 15 river miles below Glen Canyon Dam. Lees Ferry is the last developed area river runners will see until Phantom Ranch, nearly 90 river miles away. It has a campground, parking (with a 14-day limit), public phones, a ranger station, toilets, and water.
Many of the wood or stone resthouses along the canyon’s corridor trails were built by the Civilian Conservation Corps (CCC) in the 1930s. The CCC was a Great Depression-era program that provided jobs for young men at parks and forests throughout the United States, including firefighting, tree planting, trail and road building, and other construction projects. Several CCC companies created much-needed infrastructure at Grand Canyon.
On the Bright Angel Trail , Mile-and-a-Half Resthouse has toilets, an emergency phone, and seasonal drinking water (May-Sept.). Three-Mile Resthouse has an emergency phone and seasonal drinking water (May-Sept.). River Resthouse, at mile 7.7, where Pipe Creek joins the Colorado River, has an emergency phone.
On the South Kaibab Trail , Cedar Ridge Resthouse, 1.5 miles below the rim, has toilet facilities. At 4.4 miles, the Tonto Trail Junction Resthouse has an emergency phone. The Tip-Off, a few steps farther along, has toilet facilities. No water is available along the South Kaibab Trail.
On the North Kaibab Trail , there are toilet facilities and occasional seasonal water at Supai Tunnel, two miles from the rim. Roaring Springs, at 4.7 miles, has toilet facilities and seasonal drinking water (May-Sept.).
Xanterra, the park’s South Rim lodging concessionaire, offers daily pack-mule services year-round for backpackers and river runners who need assistance shuttling their gear between Phantom Ranch  and Grand Canyon Village . There’s a weight limit of 30 pounds, and fees run about $70 one-way. Advance reservations are necessary, and items must be properly packed and delivered to the drop-off points by a specified time.
For details or reservations, contact Xanterra (303/297-3175 or 800/297-2757, www.grandcanyonlodges.com ). If you don’t have your own duffel bag, you will be provided (no kidding) with a repurposed grain sack.
It’s highly unlikely that your cell phone will pick up a signal inside the canyon. Consider leaving the phone at home or at the rim; electronic devices can be downright irritating to backpackers and river runners who cherish natural quiet.
The emergency phones available at some resthouses and campgrounds are connected to a 24-hour dispatch center and do not require coins. Rangers patrol the trails and river, and ranger stations are located at Indian Garden , Bright Angel Campground , and Cottonwood Campground  (unstaffed in the off-season). River guides carry satellite phones, and they are trained to assist with emergencies.
Stay on established trails: On numerous occasions, hikers have been rescued only yards away from a trail. The National Park Service rescues about 400 visitors each year, and most are first-time canyon hikers. If you require rescue, you will be responsible for the cost. Exhaustion doesn’t constitute an emergency.
You can leave the park administration telephone number (928/638-2477) with someone who is aware of your itinerary. If you’ve told your contact you will call after hiking out of the canyon, be sure to do so to avoid unnecessary search-and-rescue efforts on your behalf.