We have some counties in our state that are starting to charge a fee for us to pay escrowed RE taxes electronically. Let's say it is $5 per installment, per loan. Can you charge this $5 to each borrower's escrow account as long as it shows up in their annual activity statement?

Most likely depends on your escrow/loan agreement.

I have always been of the opinion that 17(c) would prevent the bank from charging anything extra in the escrow account other than the anticipated disbursements and the allowable cushion. Maybe it would be acceptable if the fees were outside of the escrow account itself.

(c) Limits on payments to escrow accounts. (1) A lender or servicer (hereafter servicer) shall not require a borrower to deposit into any escrow account, created in connection with a federally related mortgage loan, more than the following amounts:
(i) Charges at settlement or upon creation of an escrow account. At the time a servicer creates an escrow account for a borrower, the servicer may charge the borrower an amount sufficient to pay the charges respecting the mortgaged property, such as taxes and insurance, which are attributable to the period from the date such payment(s) were last paid until the initial payment date. The ‘‘amount sufficient to pay’’ is computed so that the lowest month end target balance projected for the escrow account computation year is zero (–0–) (see Step 2 in Appendix E to this part). In addition, the servicer may charge the borrower a cushion that shall be no greater than one-sixth (1⁄6) of the estimated total annual payments from the escrow account.
(ii) Charges during the life of the escrow account. Throughout the life of an escrow account, the servicer may charge the borrower a monthly sum equal to one-twelfth (1⁄12) of the total annual escrow payments which the servicer reasonably anticipates paying from the account. In addition, the servicer may add an amount to maintain a cushion no greater than one-sixth (1⁄6) of the estimated total annual payments from the account. However, if a servicer determines through an escrow account analysis that there is a shortage or deficiency, the servicer may require the borrower to pay additional deposits to make up the shortage or eliminate the deficiency, subject to the limitations set forth in §1024.17(f).