Recommended PSI range used during professional hydro jetting for commercial grease lines

Professional hydro jetting for commercial kitchen grease lines requires a pressure range of 3,500 to 4,000 PSI at a flow rate of 12 to 18 GPM to scour solidified fats without damaging structural piping.

Commercial kitchen waste carries heavy concentrations of fats, oils, and grease (FOG) that cool and coat pipe walls, restricting diameter and causing severe backups. The EPA estimates that grease accumulation causes roughly 47% of all sewer line blockages in the United States, forcing facility managers to balance aggressive clearing against the structural integrity of aging drain lines.

If you only do one thing: Pair 3,500 PSI with hot water heated between 140°F and 160°F to liquefy hardened grease deposits rather than simply dislodging cold chunks downline.

• Pressure calibration: Operate between 3,000 and 4,000 PSI (pounds per square inch) to shear grease off interior walls, as pressures under 2,500 PSI only punch temporary pilot holes through dense grease blockages.
• Flow rate sizing: Maintain 12 to 18 GPM (gallons per minute) on standard 4-inch to 8-inch commercial mains to ensure sufficient water mass flushes loosened solids directly to the grease trap or municipal interceptor.
• Thermal application: Run water at 140°F to 160°F through a commercial burner unit, which cuts clearing time in half by emulsifying grease that cold water would otherwise redeposit downline.
• Nozzle selection: Deploy a rotating 360-degree nozzle with rear-firing propulsion jets cut at 30-degree angles, which pulls the hose down the pipe while scouring the full circumference of the drain wall.
• Substrate safety limits: Cap working pressure at 3,000 PSI when servicing aged PVC (polyvinyl chloride) or vitrified clay lines to prevent seam blowout or joint failure while still eliminating waste accumulation.

• Watch out for: Downstream blockages caused by low water volume under 8 GPM, which breaks grease into large chunks that dam lower junctions instead of washing completely clear.
• Watch out for: Structural blowouts in degraded cast iron piping when exceeding 4,000 PSI, which can blast through corroded bottom walls and cause leaks beneath slab foundations.
• Watch out for: Jetting without an initial CCTV (closed-circuit television) video inspection, risking line collapse if grease accumulation is masking cracked pipe walls or joint offsets.

Perform a baseline camera inspection to verify pipe material and wall condition before setting pump pressure, scheduling high-volume commercial kitchens for service every 3 to 6 months. For site assessments or emergency drain line clearing, contact ARS/Rescue Rooter at 866-399-2885.