Property Tax calculation for new construction

[Columbiaheat5]

What property tax calculation will be used in reference to my monthly payments on a new constructed home? For example the current property tax on the property that was bought for the new construction was 5,000 at end of 2013. When my house is completed the property tax will most likely be changed to 13,000 some time in 2014. In Illinois we pay the tax on the previous year as we would pay 2013 in May and September. So do lenders use the monthly average of the 5k or 13k when going through DTI process? Thank you all for the help...I just hear many different stories and wanted to get the right one.

[ShanetheMortgageMan]

The lender will require a "tax cert" to be done by the title company, certifying how much the property taxes will be after the home is completed.  The title company will contact the county and do some calculations to figure out what they would eventually be.  That figure is what will be used to calculate the property taxes, not an average of the two years or anything.