Water pressure in PSI and GPM settings required for jetting 1.5-inch kitchen sink grease lines

For 1.5-inch kitchen sink grease lines, set hydro-jetting equipment between 1,500 and 2,000 PSI with a flow rate of 1.5 to 2.2 GPM using a 1/8-inch ultra-flexible micro-hose and specialized degreasing nozzle.

Kitchen sink drain arms (1.5-inch diameter) present high resistance due to tight 90-degree elbows, short sweep sanitary tees, and heavy grease accumulation. Mechanical cables often bore narrow holes through solidified blockages, whereas high-pressure scouring shears fats, oils, and grease (FOG) flush from pipe walls without overwhelming interior fixtures.

If you only do one thing: Pair a 1/8-inch micro-hose with a rear-facing scouring nozzle calibrated to deliver under 2.2 GPM (gallons per minute) to prevent indoor basin overflow.

1. Pressure calibration: Regulate pump output between 1,500 and 2,000 PSI (pounds per square inch). This range produces adequate shearing velocity to blast congealed fats from pipe walls without exceeding the joint tolerances of aged PVC, ABS, copper, or galvanized drain lines.
2. Flow rate restriction: Maintain water flow between 1.5 and 2.2 GPM. Standard 1.5-inch drain piping possesses limited volume capacity; exceeding 2.5 GPM will overwhelm the fixture trap arm and cause indoor backup out of the sink basin.
3. Hose and nozzle selection: Deploy a 1/8-inch micro-bore hose rated for 3,000 to 4,000 PSI burst tolerance to negotiate tight 1.5-inch bends. Fit the hose with a grease nozzle featuring three rear-facing jets at 30 to 45 degrees and one forward-facing piercing jet (0.015-inch to 0.020-inch orifice diameter).
4. Thermal enhancement: Supply hot water between 120°F and 140°F (49°C to 60°C) into the jetter pump feed if equipment allows. Hot-water scouring emulsifies grease deposits significantly faster than cold water at lower operating pressures.
5. Feed and retrieval technique: Pulse the hose downstream through the grease plug, then draw back slowly at approximately 1 foot every 3 to 5 seconds to peel residue off pipe walls. ARS/Rescue Rooter Scour Jet equipment relies on controlled retraction rather than forward pushing to leave the line completely clear.

• Watch out for: Exceeding 2,200 PSI on thin-wall tubular drain assemblies or corroded galvanized steel, which blows out threaded hub joints and causes structural leaks behind walls.
• Watch out for: Using standard 1/4-inch jetting hoses instead of 1/8-inch lines, which bind tightly in 1.5-inch quarter-bends and risk jamming permanently inside wall cavities.
• Watch out for: Omitting downstream drain protection, allowing dislodged grease chunks to redeposit into 3-inch or 4-inch building mains and shifting the blockage further down the system.

Verify pipe material and fitting layout through an access point inspection before pressurizing the pump, and contact ARS/Rescue Rooter at 866-399-2885 for professional drain diagnostic services backed by the Exceptional Service Guarantee.