Why is my basement floor drain backing up?

What does it mean when water comes up through a basement floor drain?

Water coming up through a basement floor drain usually means the sewer line from your house to the city sewer main is blocked. The floor drain is often the lowest opening in your plumbing, so when water can’t get out, that’s where it shows up first. The City of New Westminster lists tree roots, grease and foreign objects as the usual causes of sewer service blockages.

If the floor drain fills when someone upstairs flushes or runs the washer, and the basement toilet gurgles, the sewer line is the likely problem. If only the floor drain acts up, the blockage may be in its own pipe.

Is the blockage in my pipe or the city’s sewer main?

A floor drain backup can start in your own sewer line or in the city sewer main, and a plumber or a city crew can tell you which. If your neighbours have the same backup, or yours started during heavy rain, the problem is more likely in the city sewer main. The City of Burnaby tells residents with sewage spewing out, or a basement flooding in heavy rain, to call its emergency dispatch for immediate attention.

What should I do when my floor drain backs up?

When a floor drain backs up, get outside first if you smell gas. Otherwise, stop running water and stay away from the sewage.

1. If you smell rotten eggs, treat it as gas even if you think it’s sewage. FortisBC says that smell could be a gas leak. Don’t touch light switches or use your phone inside. Go outside and leave the door open behind you. Once you’re out, call the FortisBC emergency line or 911.
2. Hold off on flushing and laundry until the line is clear. New Westminster advises shutting off all sources of water to control a sewer backup.
3. Stay out of water that could reach anything electrical. BC Hydro says not to enter flooded basements that may have energized wires or appliances. If the water reached your furnace, water heater or other gas or electrical equipment, Technical Safety BC says not to turn those items on until a licensed gas or electrical contractor has looked at them.
4. Leave the cleanout cap on, since a backed-up line can push sewage out of it with real force. Skip chemical drain cleaner too. It won’t reach a blockage under the yard, and it sits in the dirty water where it can splash you or whoever clears the line.
5. Call a plumber, and report the blockage to your city if its rules require it. Surrey’s bylaw requires homeowners to notify the City of a blockage in their sanitary or storm service.
6. Take photos and call your insurance company. Surrey notes that many insurance policies cover sewer backups.

Is sewage from a floor drain dangerous?

Yes. Treat anything that came up through a floor drain as sewage, which can make you sick, and keep children and pets away from it. Health Canada warns of a real danger of infection from breathing the air where sewage has spilled and from handling contaminated water and materials. It says children, pregnant women and people with breathing problems should never handle it.

Surrey advises calling a professional plumbing or restoration contractor after a sanitary backup. If you have to go in first, HealthLink BC’s clean-up advice calls for puncture-proof waterproof boots, protective gloves, eye protection and a well-fitted respirator such as an N95 mask, and washing your hands often. Health Canada notes that a house and its furnishings are less likely to grow mould if they’re dried within 48 hours.

Who is responsible for a blocked sewer line, me or the city?

In Surrey and New Westminster, you’re responsible for at least the part of the sewer line on your own property, and the city looks after its sewer main. Who handles the stretch in between depends on the city.

Surrey makes property owners responsible for keeping the sewer connection on their property clear and working. When a blockage is reported, City crews work out whether it’s in the main or in the service on the City side of the property line.

In New Westminster, the owner is responsible for the sewer service from the building to the City main, unless an inspection chamber at the property line is full or the main itself is blocked. The owner pays all charges for work on that line.

How does a plumber clear a backed-up floor drain?

A plumber gets into your sewer line through a cleanout and clears the blockage as far as your city’s rules call for. New Westminster tells homeowners to make sure their plumber tries to clear the blockage to the municipal sewer main or inspection chamber, instead of stopping at the property line.

1. The plumber finds an access point, usually a cleanout inside the house or just outside it.
2. They cut through the blockage with a drain machine, a motorized cable that chews through roots and packed debris.
3. If grease or sludge is the problem, they hydro jet the line. High-pressure water scours the pipe walls and flushes debris downstream.
4. They test the line by running water at the fixtures that were backing up.

How do I keep my floor drain from backing up again?

You can lower the odds of another backup by keeping wipes and grease out of your drains. Metro Vancouver says pee, poo, toilet paper and bodily fluids are the only things safe to flush, so wipes go in the garbage even when the package says flushable.

Some homes have a backwater valve, a one-way device that closes when sewage flows back toward the house from the city sewer main. It won’t stop a backup caused by a blockage in your own line. The Government of Canada says one should be installed by a licensed plumbing professional, after checking permit rules with your local government.

When to call a plumber

Call a plumber as soon as sewage comes up through the floor drain, or if the drain keeps backing up after it’s been cleared. If water keeps rising after everyone has stopped using water, or your neighbours have the same problem, call your city as well, because the water is likely coming from the city side. If you smell gas, leave first and call FortisBC or 911 from outside.

DrainX clears mainline and sewer backups with drain cleaning and hydro jetting, and does emergency plumbing when sewage is already coming into the basement.