Sonoma County's Board of Supervisors today is set to authorize spending up to $22.4 million over the next four years to replace the county's aging accounting and budgeting system.

The upgrade to new computer software and hardware is one of the county's costliest capital projects in recent years.

But county officials say it is a long-delayed replacement.

Assistant Auditor-Controller Donna Dunk called the system the "backbone" for county government, including more than two dozen departments and agencies, 3,500 employees and an annual budget of $1.2 billion.

The current system is nearly 28 years old, runs on outdated equipment and has an operating program -- FAMIS -- that has little industry support, officials said. It was tagged for replacement in 2000, but other technology upgrades came first. The recession meant additional delay.

The project's re-emergence comes amid a forecast of a slow rebound in government revenues and could signal a willingness by the Board of Supervisors to embrace spending that wasn't possible a few years ago.

But the move comes with risks.

Marin County spent $5 million in legal fees to press its case that taxpayers were ripped off when the county's new computerized accounting system failed to work properly. The county scrapped the system, which had cost taxpayers an estimated $28.6 million by 2009. The county announced a $3.9 million settlement in the case last month.

Sonoma County officials acknowledged the risk but said they structured their contracts in a different way and sought outside legal help to minimize potential pitfalls for the project.

The overall cost is sure to raise some eyebrows. It is more than twice what the county paid for the personnel and payroll system upgrade, completed in 2011. It also comes amid the county's continued struggle to pay for core services, including road upkeep, and battles with employee groups over pay and benefits.

But officials said contracts at the core of the project were vetted by an association of government finance officers, which they said found costs competitive with similar accounting system overhauls.

Purchase of a new PeopleSoft program from Oracle accounts for only $946,000 of the total.

Implementation of the system will be handled through a $5.5 million contract with Ciber, a Colorado-based computer consultant. Work by county staff members will add $6.2 million. The upgrade is set to start next month and largely wrap up by July 2015.

License fees, maintenance, training and hardware purchases will account for roughly $4.3 million.

Outside project management, legal services and audit oversight will account for $1.7 million. Other administrative and supply costs will total nearly $780,000, with $2.7 million in contingency money set aside for project changes and cost overruns.

The county hopes to pay for the project out of yearly budget allocations through 2016-2017, with each associated department chipping in its share.

Most of the cost this fiscal year is set to come from $3.9 million in tobacco settlement money. Fixed-rate financing from Oracle will kick in $1.3 million.

If needed, variable-rate loans from Oracle and the county treasury could be used in future years to pay for the project.

You can reach Staff Writer Brett Wilkison at 521-5295or