Find and open it
- Look for a lid set into the basement slab, most often a metre or two inside the front foundation, over the main drain's exit. The lid may be round or square and is often screwed or clipped down. Lift it with gloves on.
- Inside you will see the valve body with a clear or solid cover. Many have a removable cover held by clamps or screws.
Inspect the flap
- With the cover off, look at the flap. It should hang freely and move easily when nudged. Remove anything caught on it or under it: paper, wipes, grease. Rinse it with a hose or bucket of water.
- Check that the cover gasket is intact before closing up. A damaged gasket lets sewer gas escape.
During a storm
- Once the municipal sewer surcharges, the flap swings shut. While it is closed, water from your house cannot leave. During heavy rain, avoid running the washer, dishwasher and showers, and limit toilet flushes until the storm passes.
- Water at a floor drain mid-storm despite the valve suggests debris under the flap, or a second drain connected downstream of it.
Quick checklist
- Open the access lid
- Check the flap moves freely
- Remove debris and rinse
- Check the cover gasket
- Reduce water use during storms
When to call
- If the flap is damaged, the cover cracked, or the valve shows signs of leaking, a plumber should look at it. Some valves have replaceable flaps.
- Unsure whether one was ever installed? Check the slab along the street-side wall for a round or square cover.
Why it matters in Richmond Hill
- Heavy summer storms have caused sewer back-ups in parts of York Region over the years. A backwater valve that is clogged or jammed open gives no protection at all, which is why maintenance matters as much as installation. Some insurers ask whether a valve is present and maintained.
- Keep a note of when you last checked it, next to the date you test your sump pump.
Richmond Hill note: most houses here sit on York Region municipal water with fairly hard supply, and many basements have a floor drain tied to the sanitary lateral. Mention both on the phone; it changes what goes on the truck.
Want a second opinion on your own pipes first? Dial (365) 363-1575; the person answering holds the wrench.