Sewer Backup and Backwater Valves: What Saskatoon Buyers and Homeowners Should Know

Not All Basement Flooding Comes From Outside

When most people think about a flooded basement, they picture water coming in from the yard: overflowing eavestroughs, poor grading or a window well filling up during a storm. We've covered those in our guide to protecting your house from rain damage, our tips for improving your lot grading and our sump pump best practices.

There's a second kind of basement flooding that catches many Saskatoon homeowners off guard: sewer backup. Instead of seeping in through the walls, water comes up through the floor drain, toilet or shower. It's messier, harder to clean up and often handled differently by insurance. The good news is that a small device called a backwater valve can go a long way toward preventing it.

How Sewer Backup Happens

During a heavy downpour or rapid spring melt, the City's sewer system can get overwhelmed. When the pipes under the street fill up faster than they can drain, water and sewage can flow backward through the sewer line into the lowest openings in your home, usually the basement floor drain.

Older Saskatoon homes can be more exposed. In many of them, the weeping tile (the drainage pipe around the foundation) was connected straight to the basement floor drain. That means groundwater around the house flows into the sewer line too, adding to the load during a storm. Newer homes typically send weeping tile water to a sump pit instead, where a sump pump pushes it outside.

What a Backwater Valve Does

A backwater valve is a one-way flap installed on your home's main sewer line, usually under the basement floor with an access cover. Wastewater can flow out of the house normally, but if sewage starts flowing back toward the house, the flap closes and blocks it.

The City of Saskatoon has required backwater valves in new homes since 2003. A City stormwater manager reported in 2011 that backwater valves eliminated sewer backup in about 85% of cases in homes that had them, and greatly reduced the damage in most of the rest. Many homes built before 2003 don't have one unless a previous owner added it.

A backwater valve and a sump pump do different jobs. The sump pump moves groundwater out of the weeping tile. The backwater valve keeps sewage from coming back in. Many homes benefit from both.

If You're Buying a Saskatoon Home

Water problems are among the most expensive surprises a buyer can inherit, so make them part of your due diligence:

• Check the year built. A home built before 2003 may not have a backwater valve. Ask whether one has been added and when.
• Ask about past water. Review the seller's Property Condition Disclosure Statement for past flooding or sewer backup, and ask about any insurance claims.
• Have your inspector locate it. Ask your home inspector to find the backwater valve access, the sump pit and the floor drain, and to note signs of past water in the basement.
• Consider a sewer line camera inspection. In older, tree-lined neighbourhoods like Nutana, City Park and Caswell Hill, a plumber can scope the line to the street to check for root intrusion, cracks or sagging pipe.
• Get an insurance quote early. Sewer backup coverage is often an optional add-on, and a home's history and protection can affect what's available. Get the quote before your conditions come off.

Bring our home viewing checklist to showings to spot water warning signs before you even get to the inspection, and see our Saskatoon Home Buyer's Guide for how inspections and conditions fit into the buying process.

If You Already Own an Older Home

• Find out what you have. Look for a round or square access cover in the basement floor near where the sewer line leaves the house. If you're not sure, a plumber can tell you.
• Add one with a permit. Installing a backwater valve means opening the floor and working on your sewer line. Use a licensed plumber, and confirm the plumbing permit the City of Saskatoon requires for this kind of work.
• Maintain it. Check the valve once or twice a year, clear debris from the flap and make sure the access cover stays easy to reach. A valve that's stuck open won't protect you.
• Know what to do in a storm. When the valve is closed during a backup, water you use in the house has nowhere to go. During heavy rain, go easy on laundry, dishwashers and showers.
• Check for help with the cost. The City has offered flood protection programs and home flood risk assessments in the past. Check saskatoon.ca for what's available now.

If You're Selling

Buyers notice basements. If you've added a backwater valve, upgraded your sump or had the sewer line repaired, keep the receipts and permits and share them. Records like these answer a buyer's questions before they ask. Our Seller's Guide includes a printable Home Improvement Record Sheet to keep it all in one place, and My Selling Plan helps you map out what to do before you list. Be honest about any past water on your Property Condition Disclosure Statement, and ask your lawyer if you're unsure what to include.

Sewer Backup FAQ

How do I know if my Saskatoon home has a backwater valve?

Look for an access cover in the basement floor near where the main sewer line exits the house. Homes built in Saskatoon since 2003 should have one. For older homes, check your records or ask a plumber or home inspector to confirm.

Does a sump pump protect against sewer backup?

Not on its own. A sump pump removes groundwater collected by the weeping tile. A backwater valve blocks sewage from flowing back into the house. They solve different problems, and many homes benefit from both.

Does home insurance cover sewer backup?

Often only with an optional sewer backup add-on, and limits vary. Ask your insurer exactly what's covered, especially when buying an older home or after adding a backwater valve.

Should I get a sewer line inspection when buying an older home?

It's worth considering, especially in mature neighbourhoods with large trees. A camera inspection can reveal root intrusion or damaged pipe that a standard home inspection can't see.

More questions about buying or selling in Saskatoon? See our Saskatoon Real Estate Questions & Answers.

Questions About a Home's Basement?

Whether you're buying, selling or just trying to protect the home you have, we're happy to help you know what to look for. Talk to Clayton and Jessica, your trusted REALTORS®: call or text Jessica at 306.241.6029 or Clayton at 306.341.4401.

This article is general information, not plumbing, insurance or legal advice. Confirm requirements and coverage with a licensed plumber, the City of Saskatoon and your insurer.