The normal water pressure in a commercial building typically ranges between 40 to 80 pounds per square inch (psi). However, the exact water pressure can vary based on factors such as the building's height, location, and local regulations. Water pressure that falls below 40 psi might result in inadequate flow, while pressures exceeding 80 psi can strain plumbing components and appliances. Regular monitoring and, if necessary, the use of pressure-reducing valves can help maintain optimal water pressure levels for commercial buildings.