Abstract: The Ford F-750 model water truck utilized to wash down a retaining wall at the construction site was not checked at the beginning of each shift to assure that the brake was operational and that the safety devices (wheel chocks) were in safe operating condition and put in use. Employee #1 and the owner had parked the truck on an approximately 10-percent grade where it ran for approximately 20 minutes prior to the accident. The truck was left to idle due to power being needed to run the pumps. Employee #1 was using a hose approximately 100 ft long and had started washing the wall slightly above where the truck was parked. At the time of the accident, Employee #1 was approximately 60 ft below the truck when it began its descent down the slope toward Employee #1 who was not aware of its movement until impact. Employee #1 was killed.