Fairfax County Executive Leonard Whorton promised yesterday there will be no tax rate increase next year and urged citizen review of the way the county government spends its money, collects its taxes and runs its day-to-day operations.

Wharton's proposal is the result of pressure from members of the Board of Supervisors, who say they fear taxpayer revolt of the sort that produced Proposition 13 in California.

His proposal calls for the creation of three citizen committees to examine the county's social needs, its tax structure and the efficiency of its government.

"These committees will give the county a complete physical examination, seeing if we are putting on weight anywhere and looking to see if we are starving ourselves elsewhere," Whorton said.

The county executive, who will send his proposal Monday to the Board of Supervisors, said he couldn't promise the "physical examination" by the committees would reduce the cost of county government, but "as a result of this review, the taxpayer can feel fairly confident his taxes are used efficiently."

If Whorton's proposal is adopted, the committees, made up of members from across the county and of representatives of civic and business groups, will present reports next spring to the Board of Supervisors when the board undertakes its annual budget deliberations.

Whorton yesterday rejected as unrealistic proposals by Supervisor Audrey Moore (D-Annandale) and Board Chairman John F. Herrity (R) that the county government limit its spending next year to an increase of no more than 5 percent over this fiscal year.

"A limitation like that would make it impossible for me to make a realistic assessment of the needs in the county and of the means available to finance those needs. I would basically tell everybody (who wants more money) no," Whorton said.

The county's annual operating budget for fiscal 1979, which began on the first of this month, calls for a 9.9 percent increase in spending over the previous year.

Moore said yesterday a spending limit is necessary because government "is very unlikely to cut its own spending" without it.

"People in private business have to operate under financial restraints," Moore said. "It just isn't very much fun. Without the restraints, governments will spend whatever it has to spend."

Although Whorton promised yesterday to head off any tax rate increase, he said he could not promise that homeowners in the county won't have to pay higher property taxes next year.

This year, despite a 10-cent reduction in the tax rate from $1.74 per $100 of assessed valuation to $1.64, the owners of a $69,000 house paid about $1.246 in taxes, or $246 more than last year.

With rising real estate assessments, which last year climbed an average of 8.7 percent on county homes, a sizable tax cut would be needed to keep county residents from paying higher taxes.

Whorton said a "considerable streamlining" of county government" would be required to prevent higher taxes for homeowners.

"That old man inflation is a terrible force," Whorton said. He said the citizen review of the budget would make taxpayers "fairly confident that taxes are used efficiently."

Supervisors Marie B. Travesky (R-Springfield) and Alan H. Magazine (D-Mason) praised Whorton's plane for citizen involvement in government. Travesky called it "the most innovative way of approaching budget control that I've seen in a lonlong time."