Twenty-five Fairfax County employes are "double-dipping" on the county payroll, drawing retirement benefits at the same time they are receiving salaries for their second jobs, a practice that a new county report says will cost taxpayers more than $898,000 this year.

The controversial practice, which has been banned in most other Washington area jurisdictions, was criticized sharply by some Fairfax officials after disclosure that school officials made a $157,000-a-year offer to Superintendent William J. Burkholder.

Fairfax Supervisor Audrey Moore, a Democrat representing the Annandale area, has asked the Board of Supervisors to repeal its policies allowing employes to receive retirement benefits from one county job and full salaries from other county jobs.

"It's a ripoff of taxpayers to pay twice for the same job," Moore charged, in asking the board earlier this month to ban the "double-dipping" on the county payroll.

County officials released this week, at Moore's request, a list of the 25 employes who receive both retirement pay and salaries from the county. Nineteen of the 25 are former police officers, the report said. The Board of Supervisors also has scheduled a public hearing next Monday night to consider revamping its hiring policies.

The highest paid employe on the list is Thomas Shaw, director of the Northern Virginia Criminal Justice Academy, who receives a total annual income from the county of $62,143, according to the report. Shaw retired from the county as a police major in May 1982 with an annual retirement pay of $24,470, and was hired a month later as chief of the academy, a position that now pays $37,673 annually.

None of the 25 was mentioned by name in the report. Shaw was identified by his current position.

Some county officials, including School Board Chairman Mary E. Collier, have defended the practice, especially in the case of Burkholder, who would have lost some of his retirement benefits by remaining in his job without the additional payment proposed by the School Board.

Collier said the county benefits from the expertise of employes like Burkholder who could easily obtain jobs in the private sector while drawing county retirement benefits.

The outcry from the public and some county officials over the arrangement prompted Burkholder to announce he will retire at the end of the school year.

Although it is a common practice for government employes to receive retirement benefits from one government job while working in a second government job, the federal government and most local jurisdictions do not allow retired employes to draw both their full retirement benefits and salaries from a second job, as does Fairfax.

School employes, including Burkholder, are not listed on the report because their retirement system is separate from that of other county employes.

Retirement rules for police officers and firefighters are traditionally less stringent than those for other government employes because of the high stress factor involved in their work, according to Richard A. King, deputy county executive for public safety. King was formerly chief of police.