[BosStartup]

It's not correct that an increase in home value increases your property tax. The town has a budget which then it divides by the sum of all property values, this gives a ratio that is the tax rate per property value.

In theory, your property went up 40%, if everyone else's did too then your taxes remain the same. You can see this by viewing the tax rate over time and seeing that it has declined (but again, that didn't lower the dollar amount you must pay, just the ratio of tax to property value.)

[jerlam]

Calculation of property taxes are different across jurisdictions, you are talking like your rules apply to every system in the world.

I believe in the poster's jurisdiction, property taxes are based on a percentage of the property value and are independent of the city's actual budget.

[Mars008]

That value is usually calculated from last sale plus no more than some small percentage each year. I.e. if home 'went up in value' but didn't sell tax doesn't change much.