Hello Jday59. Thank you for taking the time to share your experience. We understand how frustrating it must have been to discover the water pressure requirement only after troubleshooting, and we apologize that this important detail wasn’t clearly communicated in the packaging or manual. Your feedback is very valuable, and we’re sharing it with our product and documentation teams to help improve future clarity for customers. A pressure washer does not create its own water supply it relies on the flow and pressure coming in from your hose or water source. Here is why around 40–45 PSI (sometimes higher) is needed: Pump protection: The washer’s pump is designed to stay lubricated and cooled by a steady flow of water. If the incoming water pressure is too low, the pump can cavitate (air pockets form), which can damage seals and pistons. Consistent performance: The washer builds on the incoming water pressure. If supply pressure is below spec, the machine may sputter, shut off, or not produce the advertised cleaning power. Trigger response: When you pull the spray gun trigger, the system suddenly demands water. Adequate inlet pressure prevents stalling or the unit shutting off. Flow rate balance: Most washers are rated for a certain gallons-per-minute (GPM) intake. Without enough pressure behind the flow, the washer cannot keep up. In short: The open water source at ~45 PSI ensures the pump is fed properly, prevents overheating/damage, and allows the pressure washer to operate at its designed power. We hope you will find this information useful. If you ever have specific questions or concerns about our products, contact Greenworks via Live chat on our website (www.greenworkstools.com), call us at 1-888-909-6757 (1-888-90WORKS) or refer to the FAQ ask section of the tool or ask us a question, anytime