Texas Local Government Code - LOC GOV'T § 71.031. Liability of New County

(a) A new county is liable for a proportionate share of the indebtedness of the county from which it was created.

(b) The new county's liability is the amount that bears the same ratio to the property value in the territory excised from the original county that the total indebtedness of the original county at the time of the creation of the new county bears to the total property value in the original county, including the value of the property in the territory excised from the original county.

(c) After organization of the new county, the commissioners court of the new county shall levy a tax on all property in the new county in order to pay the proportionate share of the indebtedness at the same tax rate as that set by the commissioners court of the original county for the payment of the debt.