Proposition 13 would change state law by deleting the two existing exclusions regarding seismic upgrades and replacing them with a single seismic safety exclusion. Currently, local property taxes are based on a property’s assessed value.
When a property is not sold or there is no new construction on a property, assessors will generally keep the value the same plus a small yearly increase for inflation. New construction, however, usually causes a reassessment if a new building is added, a building is converted to new use, or a building is renovated to appear new. The new assessed value will increase depending on the assessor's consideration of value added by the new construction. Regular maintenance and repairs do not generally raise the value of a property.
Currently, the law excludes seismic upgrades on unreinforced masonry buildings from reassessment for a period of 15 years. The law also excludes earthquake upgrades to any building without a time limit. Proposition 13 would introduce a new exclusion which would last until the property is sold and would have no time limit. Properties with masonry buildings would have their reassessment limit extended beyond 15 years. Future masonry building upgrades would receive exclusions with no time limit. Proposition 13 would mean that earthquake safety improvements made to unreinforced masonry buildings would not result in higher property taxes until the building is sold.