TroubleshootingUpdated July 17, 2026
Recurring sewer line backups cause headaches for a lot of Markham homeowners. With many houses in the area built 50, 60, or even 70 years ago, sewer pipes tend to face issues unique to our region. The flat terrain, clay-heavy soil, and history of wet basements from the Little Calumet River all combine to make sewer clogs a stubborn problem, especially in low-lying neighborhoods where everything drains slow and groundwater is common.
Why Older Markham Homes Clog
Plenty of homes here have original sewer pipes. Most are clay tile or cast iron. Both materials are tough, but over decades, they don't stand up well to roots or shifting earth. Clay pipes, in particular, develop little cracks along joints or where tree roots seek out moisture. Once roots get inside, they spread fast and catch toilet paper, wipes, and debris, causing backups that get worse with every storm or heavy use. Cast iron can also corrode and flake on the inside, forming rough spots that snag waste and slow flow. This is part of why we see so many repeat calls for the same drains.
Flat Land and High Water Table Problems
Most of Markham sits on relatively flat land. When a lot backs up to a creek, or when the water table rises after rain, sewer lines get less gravity helping move waste to the main. Clay-rich soil doesn't drain fast either, putting extra pressure on old pipes and encouraging groundwater seepage. In these spots, even a small restriction in the line is enough to trigger a backup, especially when sump pumps or laundry drains feed into the main sewer. Add in the frequent freeze-thaw cycles every winter, and pipes take a beating from ground movement too.
Common Warning Signs in Markham Basements
- Gurgling sounds or bubbles in floor drains or toilets, especially after big rain
- Water pooling around a basement floor drain or near the foundation wall
- Multiple fixtures draining slow at once, like basement toilets, tubs, and laundry sinks
- Sewage odor lingering near drains or in the utility room
- Old clay tile or cast iron pipes visible where the line exits the house
Homes near the Little Calumet River or at the bottom of a slight hill are more likely to see drains back up several times a year. The flat grade means less pressure to keep the main clear, so even a minor clog can become a bigger problem in a hurry.
What We Check When Backups Keep Happening
When our crew gets called out for recurring backups, we look past the immediate clog. We'll start with a camera inspection of the main line right at the cleanout. Old tree roots, collapsed or offset clay tiles, and thick sludge are all common sights. If a house has cast iron running under the basement slab, we search for evidence of corrosion or bellies, those low spots where water stands and grease settles. We also check sump pits and any backup sump pumps, since bad check valves or missing sump pump connections can dump extra water into the sewer during storms. Sometimes, what looks like a sewer backup is actually a failed sump pump or a broken floor drain trap. If pipes have major cracks or are shifted out of place, pipe repair or repiping may be necessary. More info on that process is on our Pipe Repair & Repiping page.
Fixes That Actually Work in Markham
Hydro jetting is often the first step. Our team sends high-pressure water through the main line to clear out roots and buildup. This works better than a snake for stubborn roots but does not patch actual cracks. For homes with repeated tree root issues, we recommend regular cleaning with an annual maintenance plan. If we find pipes have collapsed, are badly corroded, or sagging, it may be time to replace a section or the whole run. Modern materials like PVC last far longer in our clay soils and are less prone to root intrusion.
We sometimes recommend adding or inspecting a backwater valve to prevent city sewer surges from coming up into basements during heavy rain. If you notice frequent dampness or water around your sump pit, consider reviewing our Sump Pump Services page. Addressing both waterproofing and sewer line health is important in this area.
How to Stay Ahead of Trouble
- Book a sewer camera inspection every couple of years, especially in homes with original clay or cast iron lines
- Don't flush wipes, paper towels, or grease, these speed up root blockages
- Check sump pumps and backup units before big storms
- Keep an eye out for slow drains or odors and call for drain cleaning before a total clog
If you end up with a sudden backup or notice signs of a main sewer clog, quick professional drain cleaning keeps problems from spreading. For major leaks or when you suspect a broken main, our Leak Detection & Repair crew is equipped to pinpoint the issue without digging up your whole yard. And if you need more details on replacing old sewer lines or want options for upgrading your system, our main Sewer Line Services page has more info.
If you're dealing with repeat sewer backups in Markham, our team stands ready to help. Call us at 708-729-6560 for skilled troubleshooting and practical solutions that work with our local soils, pipes, and weather.