If there is even a sliver of good news that has come from the federal credit rating downgrade last week, it's come from what has not been done at the local level.

Despite earlier warnings, the AAA bond rating obtained by Prince William County is set to stay put despite problems with the federal government's rating.

Prince William Board of County Supervisors Chairman Corey Stewart (R) relayed that information Monday after being briefed by county staffers following the decision of Standard and Poor's to reduce the federal government's AAA bond rating to AA+.

"We're not in any immediate danger of losing our AAA bond rating," said Stewart.

What is significant about this is that the county largely, if not entirely, pays for major capital improvement projects through bonding, which requires borrowing money. The county then pays interest on those loans.

Having a AAA rating means that the county is virtually guaranteed not to default on its loans and can be trusted by investors to pay them back entirely with interest.

That trust means the county can pay back the borrowed money with a lower interest rate than a locality with a AA or AA+ rating.

In western Prince William County, the widening of Route 28 between Vint Hill Road and Fitzwater Drive in Nokesville is one such project being paid for with borrowed money. The county's share of the cost for the interchange at U.S. 29 and Interstate 66 is another bonded project that Stewart mentioned.

School construction if also paid for through bonding. Locally, that means borrowed money will be needed to build at school sites in areas along the Linton Hall corridor, Silver Lake and other places throughout the county.

"In fact, we just issued $40 million in bonds for the schools," said Stewart, reflecting on how the county's AAA status kept interest rates low. "We saved more than $2 million."

Such savings meant that local school officials could fast-track some construction "because the projects that they are financing are not costing as much," said the chairman.

Stewart explained that Prince William County is one of a handful of localities in the entire country that has a AAA rating from all three major credit rating groups: Standard and Poor's, Moody's and Fitch.

That "triple-triple A" status, as the lingo goes in the financial world, is held by less than one half of 1 percent of all localities in the country, according to Stewart. It's common in Northern Virginia, where thousands of local residents work for or with the local, state and federal governments.

Where the threat of a local downgrade comes from is Moody's due to the company philosophy that the localities within a nation, whether they be towns, cities, counties or states, cannot have a higher credit rating than the nation itself.

The other agencies do not share that philosophy exactly. Therefore, a federal downgrade by Moody's would trickle into states and localities whose residents are heavily reliant on the federal government for employment, such as Virginia.

Moody's assigned a "negative outlook" for the federal government but did not dock its AAA rating.

"If Moodys decides to downgrade the federal government, then we would have a problem," said Stewart.

If the commonwealth is downgraded, then the localities with the closest ties to different sectors of the federal government, such as defense, would be directly affected. Northern Virginia and Hampton Roads both are intricately linked to the Department of Defense, which is about to undergo major budget cuts.

Likewise, Prince William County would be at risk for a downgrade given its high number of federal employees and government contractors.

Virginia and the county are otherwise in good shape by market standards given that both have run surpluses in the past year.

In the county's case, Stewart mentioned that there is even a reserve fund of about $7 million dedicated for transportation funding just in case interest rates spiked or construction costs went back up.

"We're going to continue these projects regardless. We're ready for it which is why we're a AAA bond rating locality," said Stewart. "We prepare for every possible contingency."