Is there a limit on how much a deductible has to be when getting an FHA loan?

Yes. FHA caps the homeowners insurance deductible at the greater of $1,000 or 1% of the policy's dwelling coverage. Wind and named-storm deductibles get more room: the greater of $2,000 or 2% of the dwelling coverage. Since dwelling coverage is set to the cost to rebuild the home rather than the purchase price, the allowable deductible scales with the property. For most buyers this cap never comes into play. Where it bites is a policy chosen with a very high deductible to hold the premium down; that can exceed the FHA maximum and surface as a problem at underwriting. So if you are shopping insurance that way, run the deductible past your loan officer before you bind the policy, and have them check it against the current FHA handbook, since these requirements get updated.