Eastvale is a popular area, with newer homes, many parks, and some very highly rated schools. I"m very familiar with the area, having lived there myself.
Emily is correct, in that there is a base tax of approximately 1% (this is true throughout California, due to Prop. 13). Then, as with most newer neighborhoods, special assessment taxes, or mello roos, are added on to the tax bill.
These additional taxes usually pay for the development that was required for a new housing area, and will be a part of the tax bill for about 30 years in most cases. The amount will vary depending on the individual subdivisions, and in the Eastvale area it tends to range from $1,200 to about $3,600.
There is a small amount called a "CFD" that continues even once the development portion drops out, in order to cover ongoing maintenance for the neighborhood landscaping and parks.
As you can see, there is a lot involved in even this one small aspect of the homebuying process, which is why it is so important to select the right person to work with. I hope this helps, and wish you the best in your search!