An Ad Valorem Tax is a tax based on the assessed value of a property. While theoretically this is not unfair (the wealthy property owners with expensive properties pay more than those with low value properties), the adoption of Proposition 13 in 1978 has caused a major "warping" of the valuation structure in Orinda. This is due to the fact that assessed values can not increase at over 2% per year while market values can (and do). In Orinda the average home resells, on average, about once every 25 years and over that time period the assessed value becomes a smaller and smaller percent of the market value. When a home is sold, the assessed value is re-set to the market value. Two identical homes, one of which just resold and the other which has been held for 25 years, might have assessed values differing by a factor of ten.
The facts are that the top one third of assessed value homes are paying 60 percent of the ad valorem property taxes. This is not because they are the most expensive homes, but rather they are the most recently purchased homes. Their assessed values are 85 percent of their market values. Conversely, the bottom one third of assessed value homes are only paying ten percent of the ad valorem property taxes as these homes are only assessed at 20 percent of their market value. Since ad valorem taxes provide six times the total tax revenue as parcel taxes, a minority of the property tax payers (the top 1/3) pay a majority of the property taxes (60% of the total). Therefore a majority of the voters (the bottom 2/3 of homeowners with the lowest assessed values) can impose a new tax on the minority (the top 2/3 of homeowners with the highest assessed values) in which that minority pays a majority of (60% of the total) the new taxes. This is not a "minor" discrepancy. The top 1/3 of assessed value homeowners, with the same voting power as the bottom 1/3, pay six times the ad valorem tax as the bottom 1/3.
Below this discrepancyis shown as a graph. The numbers behind the graph are contained in a table. The $20 million Measure J bond which was voted on in 2014 will be repaid by $30 million in ad valorem taxes over the next 20 years which the Top One Third will pay the majority of. For the $25 million bond passed in 2016, those in the Mid 1/3 and Low 1/3 combined will end up paying less than 10 percent of the total cost.