Why is my unit not reaching high pressure? Cause Solution Diameter of garden hose is too small. Replace with a 1" (25 mm) or 5/8" (16 mm) garden hose. Water supply is restricted. Check garden hose for kinks, leaks, and blockage. Not enough inlet water supply. Open water source fully. Spray nozzle is not powerful enough. Select a higher pressure nozzle. Pump is sucking air. Check that hoses and fittings are airtight. Turn "OFF" machine, and purge pump by squeezing trigger gun until a steady flow of water emerges through the nozzle. Related articles Why does the motor buzz and fail to run? What is the life expectancy of the pump found in my unit? Why does the pressure vary from high to low? Can a foam cannon with a quick connect be used with this? How do I care for the stainless steel blade?