The McAvoy family plans to spend the next three weeks camped out in Prince William Forest Park. Not because they enjoy roughing it, but to establish residency in Prince William County.

Army Maj. Mark McAvoy, who purchased a house in the county but cannot move in until Sept. 26, was told by school officials that he would have to pay a daily tuition of $11.50 a day for each of his two older children to attend school because they were not yet official county residents.

Saying that he has been paying property taxes on his new Montclair house since he purchased it Aug. 27, McAvoy asked that the county bend its ruling that nonresidents pay tuition in county schools.

"The county gets a lot of these requests. I understand, and I have sympathy with him," said School Superintendent Edward Kelly, who denied McAvoy's request after it was presented to officials last week. "But the issue is not owning property. It has to do with residency."

Kelly said that if the McAvoys were to live in the park that he would consider them official residents and waive the tuition fee.

McAvoy, who works at Fort Belvoir and whose family has been living in neighboring Fairfax County in a rented house, said the family would pitch its tent by Monday night.

Kelly said he recently had a similar request from someone who had purchased a house but would not move into the county until late October. "Where do you draw the line?" he asked.

Currently there are 12 nonresident students paying tuition in the county, four of them on a short-term basis, according to schools spokesman Kristy Larson. Last year the county schools collected $38,000 in tuition for nonresidents.

"The county's position on our case is based on bureaucratic policy, and not the interest of children," said McAvoy. "I had hoped that the application of common sense to the policy would prevail. But it has not."

Saying he does not want to pay $322 in tuition for his two children to attend school for 14 days, he is determined to establish residency.

According to McAvoy, the school administration told him that moving the family into a hotel would meet the residency requirement. But McAvoy says he cannot afford to do that.

So this weekend McAvoy, his wife Kaye, who is expecting their fifth child in February, Nicholas, 8, Jon Mark, 7, Michelle, 4, and Jessica, 2, will set up camp in the park.

"I want to show the children that it's important to stand up for a principle if it's the right thing to do," said McAvoy, "even if it involves a little discomfort."