Voters in Prince William and Arlington counties overwhelmingly defeated bond referendums yesterday that authorized a total of $20.6 million worth of spending for parks and recreation.

In fast-growing Prince William, which has not had a referendum on parks since 1968, the vote was running more than 2 to 1 against the $14.9 million issue, which would have been used to build two controversial wave-making pools and a number of athletic and recreational areas throughtout the county.

A $4 million referendum for local parks and a $1.7 million issue for the Northern Virginia Regional Park Authority were defeated almost as badly in Arlington. The local parks question lost, 16,527 to 9,464, and the regional question, 16,160 to 9,769.

At the same time, Arlington voters approved $4.7 million for improvements on county-maintained roads by a vote of 15,616 to 10,224 and $2 million for sewer construction to prevent overflow during heavy rainfall, 16,760 to 9,222.

Though the wave-making pools generated considerable adverse publicity, the Prince William Park Authority stood by plans to build them if the referendum passed. Authority director James B. Spengler said the wave-making equipment, attacked as an unnecessary frill, would actual make the pools money-makers and help offset park authority operating expenses.

While the Board of Supervisors voted, 6 to 1, to send the referendum to voters, members either gave it lukewarm support during the campaign or were noncommittal.

The last month of the campaign coincided with steep increases in interest rates, which threatened to make the bond issues more expensive to finance as long-term debts.

In both counties, opponents of the park bonds stressed the extra cost to taxpayers in the form of higher real estate taxes.

The Arlington bond questions had solid support from the county board, as well as backing from the citizen-activist establishment. Still, the voters said no, resoundingly.