Commercial and municipal sewer jetting: combination trucks, interceptors and schedules

01 /How is commercial jetting different from residential?

Commercial jetting differs from residential mainly in scale, access and accountability. Lines are larger and longer, flows are higher, grease loads are heavier, access may be through manholes and interceptor lids rather than cleanouts, and the work often has to fit around business hours, tenants and health inspections. The owner usually needs documentation: service logs, camera video and interceptor pump-out records.

Industrial plant cleaning is a further step up again. Refineries, gas plants and upgraders use hydro blasting at pressures several times higher than any sewer rig, with lances, barriers and multi-person crews; that trade is described in hydro jetting in oil and gas.

02 /What is a combination (jet-vac) truck?

A combination truck is a single vehicle that carries a large high-flow jetter and a powerful vacuum system with a debris tank. The jetter hose is fed into a pipe from a downstream manhole and runs upstream; as the nozzle is pulled back, it drags debris to the manhole, where the vacuum boom lifts it into the truck. That keeps sand, grit, grease and root material from simply moving further down the municipal system.

These trucks clean big pipe largely with volume. Where a residential trailer jetter may run in the teens of gallons per minute, municipal combination trucks deliver many tens of gallons per minute at moderate pressures, because large diameters need large volumes of water to move material. The physics is explained in pressure vs flow, and the full range of machine classes, from cart units to combination trucks, is compared in sewer jetting machines.

• Uses: municipal sanitary and storm mains, catch basins, commercial building sewers, lift station wet wells, and interceptor clean-outs.
• Water: the truck carries a large water tank; some units recycle filtered water to reduce hydrant use, where permitted.
• Disposal: vacuumed material must go to an approved receiving site, following local rules.

03 /How are restaurant grease lines and interceptors maintained?

Restaurant grease lines and interceptors are maintained as two related but separate tasks. The interceptor (sometimes called a grease trap) is a tank or device that slows kitchen wastewater so fats float and solids settle, keeping them out of the municipal sewer. It must be pumped out on a schedule before it fills. The lines between the fixtures and the interceptor, and sometimes the line downstream of it, collect grease and are jetted on their own schedule.

1. Interceptor pump-out

   A vacuum truck removes the grease layer, solids and water. The unit is inspected for damaged baffles and outlet tees.

2. Line jetting

   Kitchen branch lines are jetted, often with a rotating nozzle and hot water, working toward the interceptor.

3. Downstream check

   The building sewer downstream of the interceptor is inspected periodically; grease here means the interceptor is not doing its job.

4. Records

   Service dates, volumes and findings are logged. Many municipalities expect records to be kept and available.

Municipal sewer-use bylaws in many Canadian cities regulate fats, oils and grease, including interceptor requirements and maintenance. The details, such as sizing, frequency and record-keeping, vary by municipality, so confirm the rules with your local utility; in Calgary, start with 311. More on residential and restaurant grease is in jetting grease lines.

04 /What are the confined space and gas hazards?

Manholes, wet wells, interceptor vaults and deep chambers are confined spaces, and sewer atmospheres can contain hydrogen sulphide (H₂S), methane and low oxygen. Hydrogen sulphide is the rotten-egg gas, and at higher concentrations it deadens the sense of smell, so the smell disappearing is not a sign of safety. Workers have died entering sewer structures, including would-be rescuers.

Most jetting from a manhole is done from the surface, with the hose fed down and the nozzle guided into the pipe with a roller or guide tube, precisely so nobody has to enter. The water-injection hazards of jetting apply here too; see water injection injuries and DIY jetters.

05 /How often should commercial lines be jetted?

There is no universal interval; it depends on grease load, pipe condition and the history of the line. A practical way to set one is to jet and camera the line, then camera it again after a set period and see how much has built up. Restaurants with heavy frying, bakeries and food processors typically need shorter intervals than offices or retail.

06 /What does a good commercial jetting contract include?

• A defined scope: which lines, from which access points, to which endpoints.
• Camera verification after jetting on a stated schedule, with video delivered.
• Service log entries that satisfy any municipal or landlord requirements.
• Emergency response terms and after-hours rates stated in advance.
• Disposal of vacuumed waste at an approved site, with documentation where required.
• A confined-space safety program for any work involving manholes or vaults.
• Clear notes on any defects found, with footage and recommended repairs kept separate from the maintenance scope.

Residential ranges are on the hydro jetting cost page. For a commercial site, the quote request form lets you describe the building, lines and interceptor so contractors can scope a maintenance plan.

07 /Who is responsible for the line: owner or city?

Responsibility usually splits at some point along the service connection between the private building sewer and the public main, but where that split falls, and who maintains the portion under public land, varies by municipality. Some cities also handle the connection at the main differently from the rest of the service. Before paying to jet a line that may be public, or asking the city to clear a line that may be private, confirm with the municipality. In Calgary, call 311. The general ownership layout is shown below.

FAQQuestions people ask