Q. At our settlement recently, the lawyer charged us $90 for a survey. When we questioned this charge, we were told it was a lender's requirement and we could do nothing about it. Just what is a survey, and is it really needed when you by a house.

A. I hope the lawyer at least gave you a copy of the survey.

It is important to distinguish between a survey and an appraisal - both of which are usually charged to the buyer. An appraisal assists the mortgage lender in assessing the value of the house so as to determine whether a mortgage should be made and in what amount. Generally, the appraisal will analyze the condition of the house, its location, structural soundness nad comparable sales in the area.

A survey, on the other hand, goes to the question of the marketability of your house. The surveyor determines whether the house is within the property borders, whether there are any encroachments on the property by next door neigbors, and the extent to which any easements on the property may affect legal title.

Lenders in the Washington area always insist on obtaining a clear "lenders" title insurance policy covering the face value of the mortgage. Title companies will issue an exception to title unless a survey has been ordered, and thus in Maryland and Virginia surveys are usually required.

Up until recently, most mortgage lenders in the District of Columbia did not require a survey, being content with their general knowledge of District property law and conditions. However, in recent years more and more lenders on district of Columbia properties are requiring a survey as a condition for obtaining a mortgage loan.

My own personal belief is that everyone buying a house should obtain a survey. It's a good idea to learn, for example, where your property lines are, and whether there are any building restrictions affecting your right to add a porch or a fence.

But, here are some suggestions involving the survey process.

First, survey prices vary all over the place I've seen them as low as $60 and as high as $150, for the same single-family lot. Ask your settlement attorney for an estimate. If it seems too high, arrange for your own survey and make sure a copy of the survey and make sure a copy of the survey gets to your lender well in advance of settlement.

Next, ask you sellers who did their survey. Unfortunately, most lenders will not honor a survey if it is more than six months old. But inquire from the prior surveyor whether the old survey can be updated and whether this will save you some money. Some of the more reputable surveyors are happy to get you business and will give you a break in the price.

You should also go to the surveyor in the Land Records Office where your property is located. They are quite helpful folks, and may be able to assist you with boundary questions, easement issues and the like.

Finally, keep in mind that most surveys will not include staking of your property will not include staking of your property corners. If you want stakes posted it will cost you a few additional dollars. You should make the necessary arrangements for stakes at the time you order the survey.

And don't forget to get a copy of the survey form your settlement attorney.