Can a landlord treat a pet deposit as a pet fee after the fact?

Without the lease defining what the "deposit" would be applied towards, and that you haven't bothered to tell us what state you are in, we can't offer much help.

I agree with you that the wording was ambiguous and that a deposit, by definition, can't be non-refundable and should be used to cover pet damages, but it's all going to come down to specific wording of state law, case law, wording of the leare, and if it made it to court, how the judge interprets the word "deposit".

If it were me, I'd research the state definition of the word "deposit" and research state laws on deposits and pet fees/deposits. If I could provide evidence that the LL is in the wrong here, I would gently and professionally let the LL know this, include a copy of the statute, and ask again for the carpet to be cleaned as part of the "deposit". So, a letter would look like this:

" Date

Dear John Smith,

As per my lease, page three, line 48, I paid a $475 "non-refundable pet deposit" at inception. State law defines a pet deposit as a "refundable security deposit paid to cover expenses like cleaning fees..." XYZ State Statute 123.45.34(b).

123.45.34(c) defines a "pet fee" as non-refundable and can be applied as the landlord wishes.

Since the lease states that I paid a deposit, not a pet fee, I would like the $200 for carpet cleaning to be deducted from my original deposit.

By state definition, deposits cannot be non-refundable, so I would also like an itemized statement, with receipts, showing how any deductions from this deposit were spent and I would like a refund of any remaining funds.

I have included copies of all above named statutes, along with the state definitions for security deposit, pet deposit, and pet fee, for your convenience.

Thank you,

Laurie Tyler"

Of course, this widely invents what state law is for you, so is just a primer, not an absolute.

Pet fee has nothing to do with apt. cleaning, it is a NON refundable fee. The cleaning would come out of deposit and not the pet fee.

You are basically getting confused by the landlord using the wrong terms. Him using the wrong terms does not change anything. When a deposit is nonrefundable it basically becomes a fee. Fees are not used for any cleaning charges. He is not breaking any laws here.

What is the difference? Pet deposits are usually non-refundable. Read your lease.

If it's "non-refundable" then it is, by definition, a "fee" and not a "deposit", since a deposit would be returned upon satisfactory completion of your obligations.

Non-refundable fee!!!