Support for property-tax limits among Prince George's County residents remains strong, but a majority, concerned about TRIM's effects on the public schools, says the charter amendment's absolute revenue freeze should be modified soon, according to a Washington Post poll.

Random interviews with 1,048 persons conducted over three consecutive days last month showed that two-thirds of those who continue to support a limit on property taxes say some modification will soon be needed.

While a plurality of 39 percent said they would still vote for TRIM (Tax Reform Initiative by Marylanders) today, 24 percent said they would oppose the measure, 17 percent would not vote and 21 percent were unsure. At the same time, 52 percent of those polled said they would raises taxes rather than cut services further.

These trends suggest a growing constituency to amend the tight limit on property-tax collections. Voters approved the limitation in 1978, and as recently as last November rejected an initiative to allow a 4 percent annual increase in tax collections and to exclude completely new commercial and industrial construction from the limit.

Those who voted for TRIM and against what was known as "TRIM Plus 4" continue to see fat in county government payrolls. But they agree with opponents of TRIM that school expenses have been pared as far as possible, and nearly one of every five thought schools were worse now.

A College Park woman who, with her husband, voted for TRIM in 1978 and would do so again today, noted that the librarian at their local elementary school was laid off. "At that point, we took our last child out of the public school, for many reasons, including this," she said.

Nearly half of all those surveyed thought public school services had been reduced under TRIM. Two-thirds said they favored increased spending for public education. Not surprisingly, 82 percent of those with children in public schools took the same view. But in a county where two of every three households have no direct stake in the schools, 60 percent of those without school-age children said they, too, want more money spent, and 42 percent of them believe schools have been hurt by the property-tax limit.

A mother with a child in private school said in an interview that while she had voted for TRIM, she is concerned about its impact on the public schools. "We must give our legislators some ability to adjust to the changing times," said the 34-year-old Bowie woman. Although she has no plans to send her children to public schools, she said she would vote to modify TRIM even if it meant a property-tax increase.

With the exception of schools, large pluralities or a majority of those surveyed said they see no evidence of reduced public services. A slim majority thought county services they used were about the same as before TRIM; 8 percent thought services were improved.

Lois Morris, a Beltsville homeowner who supported TRIM, spoke enthusiastically about recreational and library facilities that she said "seem better" than in 1978. She noted that a unit of 47 police has recently moved into a school the county closed after TRIM. Soon the officers will share the building with a new library. She blamed school problems on uncaring parents, not on TRIM.

"If I felt our police and fire departments and social services were suffering, I would take a long, hard look" at amending the tax-revenue ceiling, she said. "I'm not aware that we're short at this time."

Large majorities of those with an opinion said they noticed no reduction in police and fire protection, libraries, parks and recreation. A substantial number had no opinion on whether or not services had declined.

These perceptions stand in sharp contrast with what government officials said are marked cutbacks in spending and programs in these areas.

They contrast, too, with the view of one man polled, a veteran police officer who voted for TRIM in 1978 and then to modify it last year. Although the police force is larger now, he said there are not enough officers to respond adequately to a greater number of calls. He also noted the large number of police cruisers with mileage "up in the 90s or 100,000 miles or better."

In his own neighborhood outside Upper Marlboro, the man said, "You don't see the street cleaners out. I haven't seen one in a long time. You used to see the water-tank trucks coming around.

"I suspect come November 1984, TRIM will be changed. I think people didn't realize last time just how drastic services were being cut. Now, it's being publicized and people are beginning to notice."

Although TRIM was intended to freeze residential real estate taxes, 58 percent of those polled said their tax bills have gone up since the initiative's passage. Only 16 percent said they had remained the same.

"I expected taxes to go up some, but I'd like to know who's getting the benefits," said a Camp Springs homeowner and a TRIM supporter, whose annual tax bill has risen from $1,300 to $1,458. "I still think there's too much of a burden on property owners," said the man, a retired government scientist.

Fully three-fifths of those surveyed were married, nearly three-quarters of them in two-paycheck families. The largest number of household incomes--nearly one-third--were in the $18,001 to $30,000 range, while those earning $30,001 to $50,000 accounted for 29 percent of the random sample. The higher the income, the more residents support modification of TRIM.

Sixty-one percent of those polled were white, 35 percent black. Slightly more than half, 53 percent, were women. Forty-six percent were between the ages of 18 and 34, while 36 percent were 35 to 54, and 19 percent were over 55.

Two-thirds were registered voters. Nearly three-fourths have lived in the county for at least five years. Twenty-three percent of those polled said they had never heard of TRIM or read anything about it.