Blocked drain that keeps coming back: why plunging isn't fixing it

If you have plunged the same drain three times this year, the plunger is not the problem and neither are you. Something further down the line is catching everything that passes. Here is how to read what the drain is telling you.

One fixture, or all of them?

• One slow sink or tub is a local clog: hair, soap, grease, a toy. Annoying, not urgent.
• Several fixtures on the lowest floor draining slowly, gurgling when another one runs, or water appearing in a floor drain or shower when you flush, means the blockage is in the main drain or the sewer line. Everything in the house drains through that pipe. This is the one that turns into a flooded basement, and it is worth a call today rather than next week.

Plunging, done properly

For a sink or tub, block the overflow opening with a wet cloth so the pressure goes down the drain instead of up the overflow. Seal the plunger over the drain and work it in short, sharp pushes. For a toilet, use a flange plunger, the kind with the extra rubber lip.

If it clears and comes back within a few days, you moved the clog. You did not remove it.

Skip the chemical drain cleaners

They are hard on older pipes, they sit in a fully blocked line without doing anything, and they are dangerous for whoever opens that pipe next. Never mix two products. If you have already poured one in, tell us when you call so the technician knows what is in the line.

Why it keeps coming back

Recurring clogs almost always have a physical cause:

• Tree roots growing into the joints of older clay drains, very common across Toronto's older neighbourhoods.
• A belly, a sag in the pipe where water sits and sludge collects.
• Grease built up along the walls until the pipe is a fraction of its original size.
• Scale inside old cast iron.
• A cracked, offset or collapsed section that snags everything.

Snaking punches a hole through the blockage. The cause stays, and the hole closes again.

The camera answers it

We put a camera down the line and show you the problem on the screen, then quote from what we can see rather than what we guess. From there the fix matches the cause: hydro jetting to scour grease and scale off the walls, cutting roots and sealing the joint they came through, or a spot repair or replacement of a broken section. If the city sewer is backing up into your basement, a backwater valve stops it, and in Toronto the City's Basement Flooding Protection Subsidy Program may cover part of the cost.

When it is urgent

Sewage in the basement, water coming up a floor drain, or a toilet that backs up into the tub: stop running water anywhere in the house and call now. Every tap and flush is adding to the basement.