What the valve does for you
A downpour can overfill the street sewer and drive water backward up your lateral. Unchecked, it surfaces at the lowest point in the house, which is almost always the basement grate. The valve shuts automatically when flow reverses, keeping that water out. Many Scarborough homes have had one installed through the City's basement flooding protection program. A valve that is clogged or stuck open, though, gives no protection at all, so a little routine care goes a long way.
Your twice-yearly routine
- Find the access cover. It is normally a round or square plastic lid set into the basement floor, near the street-side wall, where the house drain exits.
- Avoid using water. Before opening the valve, make sure nobody upstairs is flushing, showering or running appliances.
- Open the cover. Twist or unscrew it. Wear rubber gloves and keep a bucket, old towels and a flashlight on hand.
- Look at the flap. Most residential valves have a hinged flap or gate with a float. It should move freely and sit closed cleanly on its seat.
- Clear debris. Pick out tissue, fat or hair clinging to the gate or its housing. A soft brush or a gloved hand is enough.
- Check the seal. The cover gasket should be intact. Replace it if it is cracked.
- Close it up. Reseat the cover firmly, then run water upstairs and listen for normal flow.
Habits that defeat it
- Running water during a backup. A closed valve traps your own wastewater too, and it will surface at the floor drain. During a heavy storm, go easy on showers, laundry and the dishwasher.
- Covering the access lid. Carpet, flooring or storage boxes over the cover make inspection a chore, so it never gets done.
- Using chemicals. Harsh cleaners can damage the flap and gaskets.
- Removing the flap. Some homeowners take it out after a slow drain. That disables the protection entirely.
- Ignoring smells. A sewer odour near the cover points to a poor seal. Our toilet fixes guide covers a different sort of nuisance, but a smelly basement is worth its own look.
Signs it needs a professional
Phone us if the gate is split, jammed, gone, or no longer seats properly. Call too if water comes up through the floor drain during a storm even with the valve fitted. That can mean the valve is installed on the wrong line, or that a second opening, such as a laundry standpipe or old floor drain, bypasses it. If the house drain itself has slowed, a full drain cleaning may help the valve work as designed.
Homes without any valve, especially back-splits and houses with basement apartments, should consider adding one. It is one of the more effective protections against basement flooding available to Scarborough homeowners.