If your house was built before 1975, then you are at elevated risk of having an oil tank on your property. Depending on which city your property is located in, natural gas was implemented as the primary fuel source at different times, in different regions.
The further your property is from Vancouver, the longer it took for some cities to adapt and implement these changes within their cities.
In approximately 1957 Vancouver switched from oil tanks to natural gas, while maple ridge implemented natural gas as late as 1975. Keep in mind that just because the primary fuel source was changed for your city at a certain time, this does not necessarily mean that you do not have a tank on your property.
It also came down to personal preference, for example: if a homeowner in Vancouver preferred oil heating as thier fuel source or wanted to upgrade to an aboveground storage tank system, your property albeit uncommon, could be fueled by an oil tank to this day.
What Happens During an Oil Tank Detection?