On July 21, 2001, at approximately 0800 mountain daylight time, a Piper PA-28-140, N6276W, was substantially damaged during a forced landing following a loss of engine power near Calhan Airstrip, Calhan, Colorado. The commercial pilot, the sole occupant in the airplane, was not injured. The airplane was being operated by a private individual under Title 14 CFR Part 91. Visual meteorological conditions prevailed, and no flight plan had been filed for the cross-country flight that was originating at the time of the accident. According to the pilot's written report, during the pre-flight examination of the airplane, he found no water in the fuel tanks. Approximately 20 seconds after takeoff, at 400 feet above ground level, the engine lost power. He attempted to restart the engine, but was forced to land in a rough/uneven field north of the airport. The right wing spar was bent, and there was substantial damage to the firewall. The pilot said that 3 months prior to the accident, the owner detected moisture in the fuel tanks, and a "drying agent" was added. The airplane was not flown between the addition of the "drying agent" and the accident. A Federal Aviation Administration Air Safety Inspector examined the airplane and found water in the bottom of the carburetor.