One the nation’s most authoritative sources for residential address data, the U.S. Census Bureau, may soon have to confront a costly legal constraint that prevents it from sharing basic street address information with thousands of county, state governments and other organizations.

The limitation not only means that state and local governments must spend more to validate address information, so must the Census Bureau and other federal agencies, according to a group of data specialists speaking at a conference on the use of geographic data.

“We share the geography, but we can’t share the information about the geography,” said Joshua Lieberman, senior manager, geospatial analytics at Deloitte.

That constraint comes in the form a privacy protection law, referred to as Title 13. It makes it against the law for the Census Bureau to disclose or publish any private information that identifies an individual or business, including address information and GPS coordinates.

While the law provides important privacy safeguards, it handcuffs those who must verify the most basic address information-much of which is already available in the private sector.

Address data is the next big release that everyone wants their hands on.” -Tom Conry

For an agency that must maintain and update a database of more than 150 million addresses, that expense is not inconsequential, acknowledged the Census Bureau’s Michael Ratcliffe, assistant geography division chief for geocartographic products and criteria.

The Census Bureau has a long history of harnessing new technologies to do the nation’s census work. Radcliffe said the 2010 census was the first time the Census Bureau was able to collect and upload census data daily, including address information, and make it available to operators in the field the next day, resulting in considerable savings for the Bureau, Ratcliffe said.

But making that information available to other government groups, including federal agencies such as the Department of Housing and Urban Development, remains beyond practical reach, Ratcliffe acknowledged.

While Title 13 technically doesn’t prohibit agencies from comparing their data against Census Bureau files, the steps involved to assure no Census address records were inadvertently acquired aren’t worth the risk of going to jail, said Tom Conry, manager of geographic information systems for Fairfax County, in northern Virginia.

Census Bureau officials responded to the concern, in a report by Federal Computer Week, saying: “The Census Bureau is exploring various possibilities to work with local governments to maintain and update its address database in ways that are totally consistent with current Title 13 confidentiality guarantees.”

“Address data is the next big release that everyone wants their hands on,” said Conry. But he doesn’t expect to tap into Census Bureau anytime soon, he said with regret.

Fairfax County is representative of thousands of county and regional government and non-governmental entities which rely heavily on place-based information to make better-informed policy decisions.

County officials are increasingly using sophisticated visualization software to plan zoning, transportation, and emergency response plans that are tied to specific locations. For instance, the county is developing 3D mapping models that would help first responders plan how to deal with emergencies in current and proposed high rise buildings in the county’s booming Tysons Corner area.

Making sure address information is not only up to date, but updated in real time, is increasingly critical, Conry said. Fairfax County, in fact, is piloting a digital data submission program so that building floor plans can ultimately be delivered to inspectors and first responders via mobile devices.

So it would be natural for Fairfax County to compare address data for new or out-of-date information with the Census Bureau–and vice versa.

Conry, Ratcliffe and other geographic information specialists, speaking at the Geospatial Summit, conducted by 1105 Media, GCN and URISA.org, a trade group, argue that a master address database would save potentially billions of dollars annually that state, local and even federal agencies could put to better use.

Ratcliffe offered just one example: When the Federal Communications Commission and the National Telecommunications and Information Administration were tasked with putting recommendations together to develop a national broadband policy, they found themselves needing a national address list that could be mapped to existing service points. Unable to use the Census Bureau list, the NTIA ultimately had to build its own list at a cost that eventually came to roughly a billion dollars, Ratcliffe said.

Multiply that example by what thousands of other government groups are spending annually to essentially maintain an address book and the potential savings nationally of a better-coordinated system would seem hard for governments to overlook.