If you can get a survey, they’re very useful. They can tell you all sorts of things – the legal limits of your property, whether there are any hydro or sewer lines, if there are any easements, even the proper location of a fence or your house. Often, however, a new survey isn’t available when you buy a house, if a survey is available at all.
If you are buying in an urban centre, the likelihood is that you don’t need a survey. It’s nice to have, to see where your lot lines are, but any encroachments from neighbours or easements that were never registered would usually be fully covered by your title insurance, so it’s not critical to have a survey up front.
Where it becomes more complicated is if you’re buying in a more rural area, and particularly if there are any questions about access to your property. Having a right-of-way to use someone else’s property to access your own can be a difficult matter to deal with; if it turns out that the travelled road is not where the legal description says it should be, the other owner doesn’t have to let you continue to use the travelled road. And then you could get stuck with no access to your property.
If you’re buying a subdivision house in town and there’s no survey, talk to your lawyer but you probably don’t need to worry. If you’re buying anything out of the ordinary, you may want to think twice before agreeing to not have a survey.