The drain service of Pure Mechanical GroupMetro Vancouver + Fraser Valley
Drain problems · Main line

Sewage coming up the basement floor drain

The floor drain is the lowest opening in the house. When the main sewer line blocks, everything you send down from upstairs comes out there. Stop using water, then read on.

Cutaway drawing of a house sewer line with a blockage under the yard and a cable reaching it
One pipe carries everything to the street

What to do right now

  1. Stop using water. No flushing, no taps, and stop the washing machine and dishwasher mid-cycle. Every litre you send down comes back up.
  2. Keep people and pets out of the water. It is sewage.
  3. If water is near outlets, a furnace or a hot water tank, stay out and switch off the power to the basement at the panel if you can reach it dry.
  4. Lift what you can off the floor and take photos for your insurer before you move anything.
  5. Call. This is the job we come out for at any hour.

What it usually means

Tree roots in the lineThe most common cause in older homes with clay or concrete sewer pipe. Roots get in at the joints and catch paper. See tree roots in the sewer line.
Wipes, grease and paperA build-up at a rough joint or a low spot in the pipe.
A collapsed or shifted pipeOld pipe cracks, sags or separates. Clearing gets you draining again; the pipe still needs repair.
The city's sideIf the blockage is past your property line, or the street main is surcharged in heavy rain, it is the city's to clear. We can tell roughly how far out the blockage is.
Only when it rainsWater at the floor drain in heavy rain with no sewage smell points at the storm side: drain tile or a sump. See drain tile and sump before the rains.

What we do when we get there

  1. Find the cleanout, the capped access to the main line. It is usually in the basement floor, near the foundation wall facing the street, or outside.
  2. Run a heavy cable with a cutting head through the line until it runs free.
  3. Flush the line with water from upstairs and watch it at the cleanout.
  4. Tell you how far out the blockage was and what came back on the cable: roots, grease, wipes or mud.
  5. If it looks like more than a clog, offer a camera inspection so you can see the pipe yourself.
Technician in an Unclog.it shirt holding a long mass of tree roots pulled from a blocked drain line
Tree roots pulled out of a blocked drain line.
Technician feeding a drain camera into an outside cleanout beside a house
A drain camera going in at an outside cleanout.

What fixing it costs

Clearing a main sewer line is from $649 in regular hours (9 to 5, Monday to Friday) and double outside them. That covers up to 2 hours on site. What a sewer line clog costs and why.

A camera inspection added to the same visit is $249. If the pipe is broken, you get a written estimate for the repair before anything else happens. Clearing the line and repairing it are separate jobs.

Questions people ask

Is this covered by home insurance?

Only if your policy includes sewer backup cover, which is usually an add-on. Call your insurer before you start cleaning, and keep photos and our invoice.

How do I know if it is my pipe or the city's?

You own the pipe from the house to the property line in most municipalities. We can measure how far the cable went before it hit the blockage. If it is past the line, we tell you and you call the city. Your city's rules.

Would a backwater valve have stopped this?

It stops the street main pushing sewage back into your house. It does not stop a blockage in your own line. Many municipalities require one on new builds; ask us when we are there.

Water where it should not be?