How to auger a main sewer line from the cleanout

01 /Where is the main cleanout in a Canadian house?

In most Canadian houses the main cleanout is in the basement, either at the base of the stack or in the floor near the wall where the sewer leaves the house, usually the front wall facing the street. It is a threaded plug or screw cap, typically 3 or 4 inches across, set in a Y or T fitting on the building drain. Some houses also have an exterior cleanout: a capped vertical pipe in the yard or beside the foundation.

If you cannot find any cleanout, that is common in finished basements and some older homes. The options are a toilet pull, entering through a floor drain (see how to auger a floor drain), or having a cleanout added. A cleanout is worth adding if the line has clogged more than once. If the house has an exterior cleanout, it is often the better entry for a lateral clog; snaking a drain from outside covers using it. Professionals occasionally enter from the roof when nothing else is available; see snaking from the roof vent.

02 /How do you open a main cleanout safely?

Open a main cleanout slowly, from the side, with a bucket and towels ready, because the building drain upstream of a clog can be full of sewage under pressure. When the plug loosens, water can spray or gush from the threads before the plug is fully out.

1. Stop all water use

   No flushing, showers, laundry or dishwasher. Ask everyone in the house.

2. Stage the area

   Plastic sheet, towels, a shop vacuum or pump, buckets, eye protection, waterproof gloves and boots. Ventilate the basement.

3. Choose the lowest safe plug

   If you have both a stack cleanout and a front-wall cleanout, open the one closest to the clog. If the drain is full, opening a higher one releases less water.

4. Loosen a quarter turn at a time

   Stand to the side, not over the opening. Let water seep out and drain away, or catch it, before loosening further.

5. Remove the plug fully

   Once flow slows, take the plug out. Set it aside with its threads protected; you will need it to seal well.

6. Let the line settle

   Allow backed-up water to drain to the level of the cleanout opening before you start the machine.

03 /What is a running trap, and how do you auger through one?

A running trap, also called a house trap, is a U-shaped trap installed on the building drain in some older houses, near where the sewer leaves the building. It has two cleanout plugs on top: one on the house side and one on the street side. Many plumbing codes no longer call for them, but they are still found in older housing stock.

To auger a lateral through a house trap, open the plug on the street side, the one downstream of the trap bend, and feed the cable toward the street. If you use the house-side plug, the cable turns back into the house drain or fights the trap bend. Running traps are also a common clog point in their own right, because solids settle in the bend.

04 /How do you set up the machine for a main line?

Set up the machine as close to the cleanout as possible, with the cable guide aimed straight into the opening, so that no more than about 30 to 60 cm of cable is exposed between the machine and the pipe. Exposed cable is the cable that whips and loops.

• Cable: 1/2-inch drum cable for a 3 to 4-inch building drain; 5/8 or 3/4-inch drum cable or 5/8 to 7/8-inch sectional cable for a 4-inch lateral, especially with roots. See the auger cable size chart.
• Head: start with a spade or C-cutter slightly smaller than the pipe for a soft clog, or a root saw where roots are suspected. See auger cutting heads.
• Guide tube: use the machine's front guide hose or a cleanout guide to protect the fitting and keep the cable from flailing.
• Power: plug into a GFCI-protected outlet. Do not use a long, light extension cord on a wet floor.
• Foot pedal: position it so you can stop rotation instantly without taking hands off the cable.
• Gloves: the manufacturer's recommended cable mitts or leather gloves designed for augering. Never cotton or loose gloves.

05 /How do you run the cable through the main line?

1. Feed without rotation

   Push cable in by hand until you meet the first real resistance. Bends near the cleanout often need a quarter turn of rotation to pass; tap the pedal rather than holding it.

2. Rotate at resistance

   With the pedal down and the machine turning forward, apply light forward pressure. Let the head cut; do not shove.

3. Watch the cable, not the drain

   If the cable starts to twist, bow or load up between machine and pipe, release the pedal immediately and pull back a few centimetres.

4. Advance in bites

   Gain 15 to 30 cm, pull back slightly, advance again. Short cycles keep the head from locking in the clog.

5. Mark the distance

   When you meet the clog, note the footage. It is the most useful fact you will record today.

6. Break through

   A sudden loss of resistance, the sound of water moving and the level dropping in the cleanout mean you are through.

7. Work the section

   Pass back and forth through the clog area several times. For roots, switch to a larger cutter and repeat.

8. Continue to the main

   If you have the cable, run on toward the municipal connection to check for a second restriction.

9. Retrieve with forward rotation

   Pull back slowly with the machine turning forward. Wipe and inspect the cable. Keep the head for inspection.

10. Flush under load

    Run several fixtures at once, or run a hose into the cleanout for 10 minutes, then flush toilets. Watch the floor drain for any rise.

Only use reverse briefly to free a head that is stuck, and never on a sectional machine except as its manufacturer directs, because reverse can uncouple sections inside the line. The drain auger safety guide covers why.

06 /When should you stop augering the main line?

• Repeated hard stop at the same distance. That is often an offset joint, a collapse, or the head catching a pipe edge. More force risks breaking the pipe or the cable.
• Roots come back on the head. You have a structural entry point. Augering buys time; see SewerRoots.ca.
• Pieces of clay, concrete or black fibrous material come back. That is pipe, possibly Orangeburg or clay tile breaking up. Stop and get a camera inspection.
• Cable is stuck and will not retract. Stop the machine, relieve the torque by letting the cable unwind, and call for help. Do not pull with the motor running.
• Water rises in the floor drain as you work. Someone is using water, or you have not cleared the clog and the line is re-filling.
• Line clears, then re-clogs within days or weeks. A clear-and-return pattern points to a defect, grease or a belly; see when augering is not enough.

Main-line augering is the job most homeowners hire out. If you do, request quotes and ask each contractor what cable size they will run, whether they will run to the municipal main, whether a camera is included, and what happens if they cannot clear it. The drain augering cost guide shows typical Canadian ranges, and SewerInspector.ca covers inspection reports. If the line needs clearing on a schedule because of roots or a belly, how often to snake a main line explains how to set the interval from your own clog history.

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