UNDERWRITING DEALS/FIGURING OUT PROPERTY TAXES HELPP!!!!

[Chad A Burge]

I am looking to purchase my first property here soon and started underwriting deals a couple days ago and thought I was doing it correctly based on asking price and everything was coming back with big cash on cash returns. Then when I was trying to calculate property tax I realized I needed to figure that out based on assessed value of the property. So now I have two issues, when I use the taxes provided by many of the PnL statements I find attached to the deals I am looking at like 3-6% cash on cash returns which I feel like is stupid low considering before that I was looking at 15-20% based off of asking prices. Second issue is I have only found one property with it's assessed value posted on the county's auditor website, all of the other properties I have looked at I can not find assessed value anywhere. 

Please help! I know I am doing something wrong when it comes to the math of the property taxes and I need help finding assessed values. 

Thanks!