Residential hydro jetting usually runs about 1,500 to 4,000 PSI. Soft grease and sludge clear at the lower end, while cutting tree roots and hard scale in a house sewer takes 3,000 to 4,000 PSI. Pressure is only half of it; water flow, near 8 to 9 gallons a minute on a four inch main, does most of the scouring.
The right setting depends on the line. Small indoor drains are cleared with higher pressure and low flow, often by a compact electric jetter around 1,500 to 2,000 PSI. The larger sewer main that leaves the house leans on flow instead, so a good rule is to match the gallons per minute at least to the pipe diameter in inches, which puts a four inch main near 8 GPM. A trade reference for jetter sizing lays out the same PSI and GPM ranges.
Pressure is matched to the pipe, not set and forgotten. A camera inspection before the work shows the pipe material and its condition, which is what decides the safe pressure, and the same camera checks the line afterward. On sound pipe, full residential pressure clears the line; on older or thin walled pipe the pressure is eased back. You can see how the service runs on the hydro jetting page.
There is no single official number. Sources and crews genuinely differ, and a jetter’s rated PSI is its figure at full throttle, so real output drops at a lower engine speed and down a long hose. For a home sewer, the flow in gallons per minute matters as much as the pressure on the gauge.