Q) I had the four corners of my land marked by a surveyor. In doing so, I noticed my neighbors' shed, which is on a concrete slab, is about three to six inches on my property. A hedge divides my land from theirs in the back yard, although the neighbors pulled out half of a hedge and use the three to six inch strip for the shed and for planting.

What is the law? I would like to keep peace with the neighbors. We did tell them that they are on the land and they said they thought the hedge belonged to them but were sorry after they found out it wasn't their property. However, our neighbors still plants on the strip. We would appreciate the simplest solution.

A) There is an old doctrine in the law known as "adverse possession." If we go back to our history books, this is also known as "squatters' rights."

The theory of the doctrine of adverse possession is that the person who holds on or uses property adversely against the rightful owner should ultimately be entitled to clear title. But not every possession of land will turn into fee simple ownership. As the name of the doctrine implies, the possession must be adverse, hostile, actual, notorious, exclusive, continuous and under the claim of the right.

These sound like highly complex legal concepts, and to some extent they are. However, in the words of one judge, "the person claiming the property by adverse possession must unfurl his flag on the land and keep it flying so that the owner may see, if he wishes, that an enemy has invaded his domain and planted the flag of conquest." Thus, the person claiming adverse possession must do something to alert the true owner that the stranger has taken occupancy.

Turning to your question, you did not indicate where you lived. In all three Washington area jurisdictions, the law -- although similar in principle -- has different time requirements for a successful adverse possession claim. In the District of Columbia, the law is that a person obtains valid title to land if the adverse possession is for 15 years. You have indicated that your neighbor has had the shed up for three years and bought her house four years ago. In Virginia the period of adversity is almost 15 years, while in Maryland the law requires 20 years for a successful claim.

The burden of proof is on the claimant -- your neighbors -- to meet the test for adverse possession. To get title to the land in question, your neighbors will have to file a complaint in court in what is known as "an action for quiet title." Needless to say, this is both time consuming and expensive, and your neighbors may not be inclined to go ahead with it.

To answer your specific question, you can avoid your neighbors' successful claim of adverse possession by removing one of the legal elements required for such a claim -- adversity.

You have indicated that you have discussed this with your neighbors. I suggest that you send them a letter, certified, return receipt requested, telling them that you recognize that they are on your land and for a limited period that you are going to permit them to keep the shed on your property.

According to one judge, "If the use by me of my neighbor's land is, on its face, permitted by my neighbor as a matter of neighborly accommodation, the use is not adverse or hostile."

Put a copy of the letter and the return receipt among your valuable papers, and periodically -- perhaps every five years -- you may want to renew the permission to your neighbor.

And don't forget if you sell your house, inform your buyers of this arrangement.

One note of caution: Under the doctrine of adverse possession, the courts permit subsequent owners to obtain the benefits of the doctrine if the 15-to-20-year period has been continuous and hostile -- regardless of who owns your property. In other words, if your neighbors sell their house, the buyer would be able to pick up the benefits of the potential adverse possession claim. Accordingly, when your neighbors decide to sell the property, I strongly recommend you insist that the shed be torn down.

Benny L. Kass is a Washington attorney. For a free copy of the booklet "A Guide to Settlement on Your New Home," send a stamped, self-addressed envelope to Benny L. Kass, Suite 1100, 1050 17th St. NW, Washington, D.C. 20036. Readers may send questions to him at that address.