Recurring downtown clogs are almost always a coated pipe rather than a single obstruction, and that is what jetting addresses.
A century of scale
Original cast iron accumulates deposit over decades until the line is a fraction of its intended bore. Cabling passes through it; jetting removes it. On peninsula pipe the difference in how long the fix lasts is substantial.
Restaurants and the hospitality trade
Downtown carries a dense concentration of kitchens on old infrastructure. Grease lines need jetting on a schedule, not on failure — a blocked line during dinner service costs more in one evening than a year of maintenance.
Rental and multi-unit buildings
Subdivided historic buildings share stacks that collect everything from every unit. Scheduled jetting is cheaper and far less disruptive than emergency work with tenants or guests in residence.
When we will decline
Very old cast iron or clay that has lost wall thickness may not take the pressure. That is what the camera is for. On a compromised line we will recommend lining instead, because jetting it risks turning a blockage into a failure.