Blog · Cambridge
Sewage backing up in your Cambridge basement: call the City or a plumber first?
When a basement floor drain in Galt, Preston or Hespeler starts pushing up sewage, the first question is whose pipe is blocked. In Cambridge the answer decides who clears it and who pays, so it is worth knowing before you pick up the phone.
Last updated September 25, 2026 · Reviewed by the Cambridge Plumbers team
Who owns the sewer pipe in Cambridge
The City of Cambridge splits responsibility at the property line. The City owns and maintains the public sewer and the section of your sewer connection (the lateral) out to the property line. Everything from the property line into the house is the owner's: the lateral under the lawn or driveway, the drain under the basement floor, the floor drain, the stack and every fixture drain. The same split applies to the water service.
That line matters because a backup looks the same in the basement no matter where the blockage is. A clog in the City main, a root mass in the lateral under your front yard and a grease plug under the basement floor all end with water coming up the lowest drain in the house.
What to do in the first ten minutes
- Stop sending water down the drains. No flushing, no laundry, no dishwasher, no showers. Every litre you use upstairs ends up on the basement floor.
- Keep people and pets out of the water. Sewage carries bacteria, and standing water near a furnace, water heater or power bar is an electrical hazard. If water is near outlets or the panel, do not wade in to reach it.
- Check whether it is only your house. If neighbours on the same street are also backing up, or it is happening during a heavy storm, the problem is more likely in the public system.
- Find your clean-out. Many older Galt and Hespeler houses have a main clean-out near where the sewer leaves the foundation. Do not open it while the line is full; it will empty into the basement. Just know where it is for the plumber or the City crew.
When to call the City first
Cambridge's Environmental Services line takes sewer backup calls 24 hours a day at 519-623-1340. Call the City first if several houses are affected, if it is storm-related, or if you have no idea where the blockage is and want the public side ruled out.
There is a step people do not expect: before the City investigates, the City asks you to contact Ontario One Call at 1-800-400-2255 for a Sewer Safety Clearance. The clearance is free. The inspection checks for cross bores: places where a natural gas line installed by trenchless boring has passed through a sewer or septic line without anyone knowing. Enbridge Gas warns that clearing a sewer with motorized equipment can damage a gas line in that spot and create a fire and explosion hazard. If you ever smell rotten eggs or hear hissing near a drain, leave the house and call Enbridge or 911 from outside. That risk is which is why homeowners and plumbers are both asked to call before clearing a blocked sewer. Having the clearance ready saves time whether the City or a private plumber ends up running the camera or auger.
The City covers the cost of clearing blockages on public property that were not caused by the homeowner. The City says fees apply if the blockage turns out to be on private property or is attributable to homeowner negligence, and it will not reimburse a private repair that it did not inspect first. In practice: if you suspect the City side, let the City look before you pay someone to dig.
When a plumber is the right first call
Call a plumber first when the evidence points inside your property line:
- Only your house is affected and the weather is dry.
- The backup shows up when your own washing machine drains or someone showers.
- The problem has happened before and a previous plumber found roots or a belly (a sag) in the lateral.
- Only one fixture or one branch is slow, which means the main is not the problem at all.
The plumber behind this site handles drain cleaning from the fixture out to the property line: augering through the clean-out, hydro-jetting grease-lined or scaled cast iron, and running a camera with a locator so you see exactly where the blockage or break sits, and how deep. That camera footage is also what you want in hand if the City side is in question, because it shows where the problem is relative to the property line.
If the backup is active and the house is filling, that is an emergency plumbing call. For what augering, jetting and camera work typically run in Cambridge, see the Cambridge plumbing cost guide.
Why Cambridge houses back up
The housing stock tells you a lot about the likely cause:
- Galt and Hespeler century homes often still drain through clay tile or cast iron to the street. Clay joints let roots in; cast iron scales and rusts until the inside diameter shrinks. Mature street trees in Galt and Hespeler make root intrusion one of the most common findings.
- Preston post-war bungalows frequently have a single original lateral carrying far more fixtures than it was built for after basement renovations.
- Newer subdivisions have PVC laterals that rarely fail on their own; backups there usually trace to grease, wipes or construction debris.
What not to put down the drain
The City and the Region of Waterloo both point to the same culprits. Wipes of any kind, including those labelled flushable, belong in the garbage. So do dental floss, cotton swabs, condoms and hygiene products. Fats, oils and grease cool and harden inside the pipe; the Region asks residents to put small amounts in the green bin instead of the sink. Medications go back to a participating pharmacy, not the toilet.
After the backup is cleared
Ask for the camera footage and the distance to the problem. If the cause is roots or a broken section, you now have a decision to make about repair or replacement of the lateral rather than clearing it every year. If the house sits low near the Grand or the Speed, a backwater valve is worth discussing so the next backup from the public side cannot enter the house. You can describe the problem here and the plumber will call back with next steps.