If you are a homeowner, or a would-be buyer, take heed: Your property taxes are going up. State and local governments derive about half of their revenue from taxes: states, largely from income and sales taxes; counties and cities, primarily from property taxes. And with housing values rising practically everywhere, homeowners are going to be easy prey for their local tax assessors. Not everywhere, of course: Some states have property tax caps to prevent local governments from making too dramatic an increase. At the same time, buyers already stretching the limits of their budgets might shun houses in areas where the property taxes are sky-high.