25 CFR § 700.81 - Monthly housing cost.
(a) General. The term monthly housing cost for a replacement dwelling purchased by a certified eligible head of household is the average monthly cost for all mortgage payments, real property taxes, reasonable utility charges, and insurance.
(b) Computation of monthly housing cost for replacement dwelling. A person's monthly housing cost for a replacement dwelling shall be a projected amount that includes one-twelfth of the estimated reasonable annual cost for utility charges.