Design & DIY

Find a buried septic tank

How can you find a buried septic tank?

The details of a septic system may be on file at your local health unit or municipal office. Then again, they may not – but in most jurisdictions these are good places to start looking. To search there, you’ll need the name of the owner at the time the system was installed (it should be in the title records) and the legal description (lot and concession number) of the property. There is usually a fee for this service.

If your system isn’t on record (and many aren’t), the place to start tracing the tank is your basement or crawl space. Find where the main sewer line exits the cottage and you’ll know the tank’s general direction and approximate depth. Newer systems often have a clean-out opening near this exit – in which case you can remove the cap and feed a garden hose into the line until it hits the baffle in the tank. Measure how much hose went in and you’ll know how far the tank is from the house.

It isn’t always that easy, of course. Older tanks are sometimes buried deep under subsequent landscaping, and occasionally directly under a cottage deck or even an addition. Tanks can sometimes be located by using a rod to probe the soil or with a metal detector (since even concrete tanks have metal handles on the pump-out lid). You can also ask around the lake about who installed the system. Often the same contractor did many of the installations and will have a record of where yours is.

If all else fails, you’ll have to find the tank the hard way, by digging down to the sewer line at the cottage end and continuing to dig along it until the tank appears.