The Fairfax County Board of Supervisors yesterday approved three steps designed to hold down the county's tax rate, but board chairman John F. Herrity later denounced the action as meaningless after the board refused to set a limit on the county's payroll and spending.

Responding to what some supervisors have characterized as taxpayer unrest, the board approved proposals for citizen committees to review county spending, tax rates and the size of the payroll.

However, the supervisors rejected proposals by Herrity and Supervisor Audrey Moore (D-Annadale) for a hiring freeze on county employes and for limiting the increase in county spending to 7 percent next year.

"This won't do any good." Herrity, the Republican nominee for the 8th Congressional District, said after the board voted against his measures. "People were expecting us to make tough decisions and we didn't do it."

Despite his objections to the steps proposed by County Executive Leonard Whorton, Herrity voted with seven of the nine supervisors to approve Whorton's plan. Moore cast the only dissenting vote.

Whorton, who had been questioned by the supervisors this spring for his management of the county government, yesterday won praise from them for what some called his "sound and reasonable approach" to controlling public spending.

Whorton called the hiring freeze and spending limit proposals "contrary to the spirit" of his plan, which he said would "impose" on the county "more rigorous discipline than a spending limitation."

Some of the supervisors said they would like to see more drastic action and cited their fears of Proposition 13, the recently approved California measure that will cut property tax rates sharply in that state.

"A complete reorganization (of county management is what is needed: our priorities are all screwed up." said Supervisor John P. Shacochis (R-Dranesville). "Im very happy to see that what was termed a catastrophe on the West Coast has made such an impression here that this [Whorton's] proposal will get serious consideration."

"This is the first major review of county structure and services to the public by a broad-based group of people," said Supervisor Marie B. Travesky (R-Springfield) "Whorton needs to be commended."

The three citizen's committees approved yesterday will include between 50 and 60 representatives of civic and business groups. They each will present recommendations on county spending, tax levels of personal requirements to the supervisors in March when the fiscal 1980 budgets is considered.

Despite promises of no tax rate increases next year. Whorton said he cannot promise county homeowners won't pay higher taxes because of rising assessments. This year, despite a tax rate reduction from $1.74 per $100 of assessed value to $1.64, the owner of a $69,000 house will pay $1,246 in taxes, or $246 more than last year.

"Whorton's proposal is a good one, but what it basically does is legitimize the process we have always been involved in." said Supervisor Alan H. Magazine (D-Mason). "If we can't affect the rate of assessment or the burden of taxation, then things are going to continue as business as usual."

In other action Tuesday, the board voted 6 to 1 to draft an ordinance that might stop Maryland from sending prisoners on work release to jobs in Fairfax County without advance notification to cunty officials. Board members approved the proposal, although several supervisors expressed doubt that such a measure could withstand a court challenge.

The board was reacting to the presence of Maryland work release prisoners working at Fairfax Heritage condominiums in Annandale last month without the knowledge of county officials. The discovery of the inmates angered several board members, and Supervisor Martha V. Pennino (D-Centerville) called it "an infringement on state rights."

Supervisor James M. Scott (D-Providence) voted against drafting the ordinance. He said the board should wait until it receives Maryland's response to a letter asking the state for prior notice in such cases.