32–50 mm (1¼–2 in) | PVC, ABS, copper, galvanized steel | Hair, soap deposits, light grease and small soft obstructions in sinks or appliance drains | Compact drum machine or small sectional cable machine | Small flexible cable, variable-speed motor, automatic cable feed, ground-fault protection | Cable: approximately 6–10 mm; low-to-moderate torque | Use flexible tooling to reduce the risk of damaging thin-wall plastic or corroded metal pipe. |
50–75 mm (2–3 in) | PVC, ABS, cast iron, clay | Kitchen grease, food residue, sludge and moderate root intrusion | Medium drum machine, sectional machine or compact water jetter | Interchangeable cutters, grease tools, forward and reverse rotation, adjustable water flow | Cable: approximately 10–13 mm; jetting: about 70–140 bar at 15–30 L/min | A penetrating nozzle is suitable for soft blockages; a rotating nozzle is better for wall deposits. |
75–100 mm (3–4 in) | Cast iron, vitrified clay, PVC, concrete | Heavy grease, compacted sludge, scale and limited root growth in branch or building drains | Heavy-duty sectional cable machine or cold-water jetter | High-torque drive, sectional cable control, pulsation function, multiple nozzle patterns | Cable: approximately 13–16 mm; jetting: about 100–200 bar at 25–45 L/min | Choose a nozzle sized to maintain rearward thrust without excessive impact on joints or fragile clay. |
100–150 mm (4–6 in) | Concrete, cast iron, clay, PVC, HDPE | Large grease deposits, sediment, recurring roots and accumulated debris in main building drains | Trailer-mounted or skid-mounted high-pressure water jetter | Large water tank, hose reel, foot valve, pressure regulation, vacuum or debris recovery support | Approximately 140–280 bar at 30–75 L/min | Flow is important for transporting debris; pressure alone does not determine cleaning effectiveness. |
150–225 mm (6–9 in) | Concrete, vitrified clay, cast iron, PVC, HDPE | Sand, silt, roots, settled solids and extensive grease in small municipal or commercial lines | High-flow jetter with root-cutting or descaling attachments | High-capacity pump, long hose, variable pressure, root saw, descaling nozzle and hose guidance | Approximately 140–250 bar at 50–115 L/min | Use a nozzle with adequate forward thrust and select pressure conservatively for cracked or displaced pipe. |
225–300 mm (9–12 in) | Reinforced concrete, clay, PVC, HDPE, ductile iron | Heavy sediment, root masses, hardened deposits and frequent storm or sanitary line maintenance | High-flow jetter, combination jet-vac unit or robotic cleaning system | Large-capacity water and debris tanks, suction recovery, rotating nozzles, remote camera inspection | Approximately 140–280 bar at 75–190 L/min | For settled material, combine jetting with vacuum recovery instead of pushing debris farther downstream. |
300–600 mm (12–24 in) | Concrete, brick, large clay pipe, steel, HDPE | Large sediment beds, roots, mineral scale and maintenance of storm or municipal sewers | Combination jet-vac truck, large trailer jetter or specialized robotic system | High water flow, vacuum excavation capability, large hose diameter, sonar or CCTV inspection | Approximately 140–250 bar at 115–300 L/min | Confirm access points, bypass requirements, water supply and downstream discharge capacity before work begins. |
| Material-Specific Consideration | PVC and HDPE | Plastic pipe with grease, soft deposits or roots | Water jetter or flexible cable machine | Adjustable pressure, smooth-edged tools and non-aggressive root-cutting heads | Use the lowest effective pressure and moderate flow | Avoid sharp tools or excessive mechanical force when the pipe wall or joints may be damaged. |
| Material-Specific Consideration | Clay and vitrified clay | Roots, displaced joints, mineral deposits and sediment | Controlled jetter with inspection camera | Pressure regulation, rotating nozzle and pre- and post-cleaning CCTV inspection | Moderate pressure selected according to pipe condition | Inspect for cracks and open joints before aggressive root cutting or descaling. |
| Material-Specific Consideration | Cast iron and steel | Grease, rust scale, mineral buildup and roots | Cable machine, jetter or descaling tool selected after inspection | Torque control, descaling nozzle, corrosion-aware pressure adjustment and CCTV capability | Moderate-to-high cleaning power, adjusted for wall loss | Severely corroded pipe may require rehabilitation rather than repeated aggressive cleaning. |
| Material-Specific Consideration | Concrete and reinforced concrete | Sediment, grease, roots, scale and hardened deposits | High-flow jetter or combination jet-vac unit | High flow, rotating nozzles, root cutters, vacuum recovery and traffic-safe controls | Flow selected according to diameter, blockage severity and debris volume | Use vacuum recovery for heavy solids and verify that joints and deteriorated surfaces can withstand the selected pressure. |