A new state law banning public school fees has teachers scrambling for supplies, parents in a tizzy over suddenly unaffordable activities and PTAs confused about how to help families.

At Fairlands Elementary in Pleasanton, the fourth-grade visit to Mission San Juan Bautista was nearly canceled. At Oak Grove High in San Jose, math teacher Kim Schaupp printed paper protractors for her geometry students because she was told she couldn’t ask them to bring real ones to class. In Pleasant Hill, middle-school band trips are at risk.

With few exceptions, state law now prohibits schools from charging fees for classroom items and activities and from requiring students to bring materials needed for school. It covers everything from 25-cent pencils and $5 binders to $350 field trips and $500 football uniforms.

Resulting from the settlement of a lawsuit against the state, the law reinforces what the California Constitution has guaranteed for nearly 140 years: a free public education.

“The court said free means free,” said Brooks Allen of the American Civil Liberties Union, which brought the suit. And “free” does not mean charging a fee and asking students to apply for a waiver or financial aid.

As the gap between government funding and education costs has widened over the years, campus charges for necessities and extras have proliferated. Many districts eliminated fees soon after the ACLU suit was settled in 2010. Now, AB1575, effective Jan. 1, bans nearly all of those fees.

Yet confusion remains, and interpretations range from near-indifference to the new law to near-paralysis over it.

“We’re not sure what we can and can’t say,” said Marilyn Weinstein, a volunteer at Fairlands Elementary, where a last-minute scramble saved the fourth-grade mission trip. Previously, parents simply paid about $35 per child. Now, she said, “we can’t tell them if you can’t afford to pay, the PTA has money for you,” because they were told that would single out low-income families. The fee has been replaced by a call for donations — which fell short.

The state and the ACLU have issued advice on compliance, such as schools may charge for dances and food but may not waive fees based on need. But in education’s trenches, the foot soldiers of fundraising are confused.

It’s at high schools where the new law poses the greatest challenge.

At Oak Grove High, the math department has $2,500 for supplies for the year, barely covering copy paper and pens for white boards. Teachers can’t ask students to bring protractors and compasses, said Schaupp, the department head. Purchasing class sets would be prohibitive.

The battle to get students to bring basic supplies is difficult when some respond — technically correctly — “I don’t have to bring anything to class,” Schaupp said.

That’s not the view at the top of the East Side Union district. “We expect kids to bring their supplies to school and to be ready to learn,” said Superintendent Chris Funk. Now it’s a fine line between conveying that expectation while obeying the law, which says students may not be graded down for not providing their own materials.

Rita Russom, a junior at East Side’s Silver Creek High, said she and other students who bought graphing calculators for Algebra II share them with students who are without.

Still, she believes students shouldn’t have to pay for such things. “It’s not really fair,” she said, noting many parents are struggling to feed families and can’t afford a $100 calculator or other supplies. She applauds the new law and hopes it will be enforced on extracurricular activities — which it covers — because she knows classmates who are shut out of athletics and the annual student dance show because they can’t afford the fees.

And while teachers applaud the spirit of the law, they feel stuck in enforcing it, many already spending hundreds of dollars of their own money in a year when they’ve lost 6 percent of their paycheck to furloughs.

Oak Grove science teacher Emanuel de Sousa said he’d like to teach a biotech course but has doubts about getting supplies like enzymes and DNA. As it is, he can’t afford to buy slides of small organisms for students to examine, with a supply budget of $5,000 for the entire 13-teacher science department.

The squeeze appears to be less tight in the Jefferson Union High School District in Daly City. The district seeks donations, Superintendent Thomas Minshew said, and fundraisers, such as the home economics department’s sales to pay for baking supplies, are ubiquitous. Yet in the PTA trenches, details of the new law aren’t clear. A fund for Pleasant Hill Elementary to attend a fifth-grade outdoor education camp in the Santa Cruz Mountains is short $6,000.

“We don’t want to exclude anyone,” said volunteer Mary Gray, but parents had to solicit donations rather than fees, and they couldn’t tell families to ask for financial aid.

News of the fee ban hasn’t reached all schools. This school year the Palo Alto High math department continued to insist Texas Instruments-89 graphing calculators were mandatory for an honors math analysis class; likewise nearby Jordan Middle School put out a list of nearly two dozen items required for sixth-graders.

Friday was the deadline for schools to set up procedures for filing complaints about suspected violations of the new law.

Parents simply wish for clarity. “This is causing a lot of upset among parents, because our hands are tied,” Weinstein said. “Where did we go so horribly wrong that all of a sudden we’re not making sound decisions?”

Contact Sharon Noguchi at 408-271-3775. Follow her at Twitter.com/NoguchiOnK12.