Construction workers do many seismic upgrades to Bay Area homes.
"We probably get asked about 10 to 15 percent of the time when someone initially calls us whether or not the improvement is going to increase the valuation," Sherry Niswander from Anderson Niswander said.
Proposition 13 on the June 8 ballot will amend the state constitution to make it clear.
Carol Lathrop is with the San Jose chapter of the League of Women Voters.
"It will make it possible for people to make safety upgrades on their property; that is, earthquake safety improvements. Their property will not be reassessed because of those improvements until the property is sold," she said.
There was confusion because buildings made of unreinforced masonry were subject to reassessment after 15 years, while stucco and frame houses were exempt until sold.
Proposition 13 would cut off a revenue source to cities and counties at a time when they really need it. However, Santa Clara County assessor Larry Stone says there's another way to look at it.
Keep in mind that the 1989 Loma Prieta earthquake did $6 billion in property damage.
"The governmental cost of cleaning up after an earthquake is significantly greater than the loss of revenue that would occur by excluding reassessibility, the cost of retrofitting a building for seismic safety," Stone said.
No one submitted an opposing argument for the state voters guide.
However, the California Nurses Association has come out against Proposition 13. Its director of public policy says it's not trying to block homeowners from getting a break. Instead, it's concerned about tax losses from large commercial properties.
"It is a commercial property tax benefit that folks are getting, and really we don't think that, given this budget situation, and the indebtedness of the state, it's one that is either necessary or one that the state can afford," Michael Lighty from the California Nurses Association said.
"I think anything that jurisdictionally government does to support and encourage seismic retrofits helps people along that whole thought process," Niswander said.