Clogged Drain or Sewer Backup? A Lower Mainland Homeowner's Guide

If one sink is slow, you have a clog. If the basement floor drain bubbles every time someone upstairs runs the shower, the problem may be in the main sewer line, and that's a different job with different rules about who pays. With the fall and winter rain here, it's worth knowing which one you're dealing with.

This guide covers how to tell the two apart, what's safe to try yourself, what a drain cleaning visit involves, and how Surrey, Vancouver and Burnaby split responsibility for the pipe between your house and the street. If your home is on septic instead of city sewer, start with our post on septic vs. sewer in BC.

One fixture, or the whole house?

Start by counting how many drains are acting up.

• One sink, tub or toilet is slow and everything else drains fine. That's a clog in that fixture's line. The City of Surrey tells residents not to call the City in this case, because it's most likely a private issue.

• Every toilet, sink, shower and tub is draining badly. Surrey lists this as a sign of a problem with the sewer service itself.

• Water or sewage comes up through the lowest drain in the house. Federal guidance on backwater valves explains that when pipes are clogged or heavy rain overwhelms the municipal system, wastewater gets forced up through the nearest exit: floor drains, toilets, sinks or shower drains, especially in basements.

• Basement fixtures drain slowly or make bubbling sounds. The City of Vancouver treats this, and an overflowing basement toilet, floor drain or tub, as a reason to call 3-1-1. An overflow on a floor above the basement is one it leaves to a plumber.

Gurgling alone doesn't prove a main line problem. Surrey notes it can also come from debris in the fixture's discharge pipe or a plumbing roof vent clogged with leaves or an animal nest.

Why backups pick up in rainy season

Your sanitary sewer is built to carry what goes down toilets and drains, not rain. Metro Vancouver calls the extra water "inflow and infiltration." It gets in through cracks caused by damage, age or tree roots, through leaky joints, and through roof and foundation drains that are wrongly tied into the sanitary line. In heavy rain that water takes up room in the pipes, and Metro Vancouver lists sewer backups and basement flooding as one result.

A large portion of it comes from private properties with damaged sewer lines or improperly connected drains, according to Metro Vancouver, and its 2019 flow data flagged high-inflow neighbourhoods in Burnaby, Surrey, Delta, both Langleys, Richmond, the Tri-Cities, Maple Ridge, Pitt Meadows and White Rock, among others.

If it's groundwater seeping in around the foundation rather than sewage coming up a drain, that's a perimeter drain and sump question. Our post on sump pumps and basement flooding risk covers that side.

What usually causes the blockage

Vancouver's list of the most common causes of sewer backups includes baby wipes, paper towels, cat litter, grease, tree roots and broken sewer laterals. Three of those come up again and again.

Wipes

Metro Vancouver ran its Unflushables campaign from 2017 to 2024, then narrowed its message to wipes alone because they're still the most flushed problem item. Even wipes labelled "flushable" don't break down quickly in the sewer. Pee, poo and toilet paper are the only things it says are safe to flush.

Grease

Fats, oils and grease harden as they move through pipes and collect other material. Metro Vancouver's "Wipe It, Green Bin It" campaign asks you to scrape small amounts into the green bin and take larger amounts, like deep fryer oil, to a depot that accepts it.

Tree roots

Roots work their way into cracks and joints and restrict flow. Surrey makes a point worth repeating: cutting them out with an auger or root cutter gets you flowing again, but roots grow back, and excessive cleaning with those tools can wear the pipe down until it fails.

What you can safely try first

For a single slow or plugged fixture:

• Use a plunger. Burnaby's advice for a backed-up toilet or sink starts there.

• Clean the strainer or stopper. Hair caught at the top of a shower or sink drain can be the whole problem. Put it in the garbage.

• Try a hand snake on a sink or tub if you're comfortable. A household hazardous waste toolkit from the Regional District of Okanagan-Similkameen recommends a plunger, snake or hose-end bladder for clearing drains.

Leave the chemical drain cleaners on the shelf. That same toolkit calls them extremely dangerous products that can cause chemical burns and permanent eye damage, and says they aren't very effective.

If several fixtures are affected, or sewage is coming up through a floor drain, stop using water. Hold off on laundry, the dishwasher and showers until the line is clear. Whatever you send down has nowhere to go but back up.

What a drain cleaning visit involves

Our drain cleaning work runs from greasy kitchen sinks and hair-clogged showers to basement floor drains, roots in the sewer line and backed-up main lines. Depending on the job, we use:

• Drain snakes for targeted blockages.

• Hydro jetting to scour built-up grease and debris off the inside of the pipe.

• Camera inspections to see what's actually in there, whether that's roots, a collapsed section or grease.

The camera matters most when a clog keeps coming back. Surrey recommends using a contractor with a sewer camera to find out how the problem happened and how to keep it from recurring. Metro Vancouver suggests a camera inspection of your sewer pipes at least once a decade.

If the camera shows a broken or root-damaged line, clearing it is a short-term fix. Vancouver lists open trenching, pipe bursting and pipe relining as the main ways to renew a sewer connection, and that work needs City permits. More on how this looks locally is on our Surrey drain cleaning page.

Who owns which part of the sewer pipe?

The pipe from your house to the city main is often called the lateral or service connection. Each city splits it differently, and the split decides who pays when it plugs.

Surrey

• Owners are responsible for sewer infrastructure up to the property line, with exceptions for some rights of way, third-party agreements and low-pressure systems.

• Most homes have an inspection chamber, usually about 300 mm (1 ft) onto City property. Don't bury it. If it's within 2 m of a driveway or in a travelled area, the owner has to put a protective cover on it.

• If the City can reach the chamber and the blockage is on its side, it clears it at no cost. If it's on the private side, the owner pays.

• With no accessible chamber, the owner has to prove where the blockage is, using a plumber's sewer camera with a City representative on site. Clearing the City side without City staff present won't be reimbursed.

• Surrey's sewer backup line is 604-591-4152. A Notice of Claim for damage has to reach the City Clerk within two months of the date of loss.

Vancouver

• You maintain the sewer lines on your property up to where they meet the City's connection.

• For blockages, the City looks at what caused it, not where it is. If no cause is found, it's assumed something improper went down from the home, and the owner pays. A two-hour weekday daytime call is listed at $386.52, tax included.

• Only an owner can request a City crew, and someone who can approve charges has to be there to sign. Without a sump or clean-out, you may need to pull your basement toilet first; crews won't remove or reinstall it.

• Licensed plumbers can clean and inspect the full connection to the sewer main. Only the City or its agents can dig up or repair the City's portion.

Burnaby

• Under Burnaby's sewer connection bylaw, the City lays the connection from the public sewer to your property line, and the owner builds the building sewer that joins the house to it.

• For a backup, Burnaby says to try a plunger, then have a plumber check the sewer line. If the plumber can't clear it to the main, call emergency dispatch at 604-294-7200.

Elsewhere, check your city's engineering department before you pay to clear the city side.

Backwater valves and sewer backup insurance

A backwater valve is a one-way valve on the sewer line that lets wastewater out and closes when it tries to come back in. Federal guidance says it should be installed by a licensed plumber, that you should check permit rules with your municipality first, and that many municipalities require one in new homes, so a house built in the last 20 to 30 years may already have one. It also needs regular inspection and cleaning to clear out dirt and grease buildup.

The Insurance Bureau of Canada says sewer backup damage is typically not covered by a standard home policy, but most insurers offer it as optional coverage, and some offer incentives for installing a backwater valve or sump pump. Call your insurer and ask whether you have it before the next big storm.

Drain backing up? Call us

If one fixture is slow, a plunger and a clean strainer might be all you need. If several drains are backing up or sewage is coming up in the basement, stop using water and call. Our plumbers are on call 24/7 for drain emergencies across the Lower Mainland. Call 604-441-3411 or book online.