Do not worry. Almost all old houses(some new houses too) have leak in the basement. It is nothing new. Most people simply ignore it. Old houses do not have 防水层. 防水层 can be expensive(over $10,000). Making a slope around your house to have better drainage may help a bit. It is better to always have HOME INSPECTION in order to avoid surprise and help make a better deal. No inspection for an old house is not right.
Since you did not see water in your basement this year. This is the best prove that your basement does not have water leak problem. This is the worst year in Ottawa, many people have basement flood and leaks.