I'll throw in my bit about Maryland. In Maryland home sellers have a disclosure or a disclaimer form that they can use to tell buyers about their property. The disclosure form is fairly extensive (about 6 pages) -- it covers things like water issues -- and the owner will tell you whether they know of any problems or not with each of the items on the list. However, an owner of a Maryland property may also still revert to a disclaimer form instead of a disclosure. In this case, the buyer should ask for more information. And even if that disclosure form was used by the seller, the buyer should still get a home inspection.
Hope that helps. Finding out as much as you can about a property before you purchase is certainly better than any of the alternatives if you find that you've purchased a property with huge problems after the fact. At least in Maryland the disclosure form is often used. Virginia doesn't even have one.
Consider the blog below. It is a list of things you could find save you from a lot of problems when buying a house. It includes a lot of things you may never have considered. Since a seller has to reply to each question asked this could save you from many hidden and not disclosed issues. Some you will have to find out yourself, some the seller will have to tell you.
If you ask the kinds of questions shown in the blog above there will be very little that is not disclosed as you covered about everything that could be an issue.