The Alexandria City Council adopted a $122.2 million budget early today that will require an increase in the number of city employes, trimming and consolidation of some popular programs and higher taxes for the average homeowner.

The higher taxes -- a 12 percent increase on the average -- will come because of higher assessments despite a two-cent reduction in the present real estate tax rate of $1.39 per $100 of assecessed valuation. The average tax increase will be $130.

The council brushed aside complaints made during more than a month of often vituperative lobbying and voted to transfer most of the functions of the city's consumer affairs office and landlord-tenant board and reduce the size of their staff.

Only the city's women's commission, among those agencies originally slated for major cutbacks, escaped unscathed.

The new budget, for the fiscal year that begins July 1, calls for 11 percent more spending than the current budget.

Some citizens who protested the consumer protection and landlord-tenant cuts indicated they felt that the survival of the two agencies represented a victory for consumers.City Manager Douglas B. Harman's original budget proposal characterized the agencies as "optional services" whose purpose should shift from counseling to legislative advocacy and education. He called for reducing the number of their employes to a skeletal one or two each.

Under the budget approved early today, the consumer affairs office, which last year processed more than 3,300 complaints and fielded more than 2,000 requests for information, will lose 1 1/2 of its four positions and be administered under the citizens asssistance program.

The landlord-tenant relations board will lose one of its six employes and fall under the city's housing office.

One of the surprises in the new budget was the increase in the number of city employes. Harman had originally recommended dropping 21 workers -- the first major reducation in more than a decade -- but the council overrode the suggestion and ordered hiring of 26 more employes, bringing the total to 1,767. City workers will get a 9.17 percent pay raise.

City officials have estimated that Alexandria could lose as much as $4.4 million in federal funds if President Reagan's budget cuts are approved.

"We may not be crumbled by an avalanche, but we are certainly getting knocked around by a lot of rocks coming down from the hill," Harman quipped before warning the council that this year's federal cutbacks will probably be only the first of many.

In addition to the agency consolidations, the council reduced the school board's requested budget by $300,000 to just under $44 million. The minimal reduction may signal a lessening in the longstanding bickering between the two city bodies. Last year, the council slashed about $1.5 million from the school board's requested budget.