Your mortgage payment has four parts. Principal, interest, property taxes, and homeowners insurance. The last two go into an escrow account, which means the servicer collects a twelfth of each annual bill every month, holds the money, and pays the county and the insurance carrier when the bills come due. Your payment went up and none of it went to principal covers why that part of the payment keeps moving.
You can often get out of escrow. Most lenders will waive it once you're at 80% loan-to-value or better, which means the mortgage balance is 80% or less of the home's value. Some charge a fee to do it, often around a quarter of a percent of the loan balance. Government-backed loans generally won't waive it at all. Call the servicer and ask two questions: what's your escrow waiver requirement, and what does the waiver cost.
The reason to bother, in Oregon specifically, is the discount. Oregon counties send property tax statements in October and give you 3% off for paying the full year by November 15, or 2% off for paying two-thirds. On a $6,000 tax bill, the full-payment discount is $180. Some servicers pay in full and pass that discount through to your escrow account, and some pay in installments and collect nothing. Look at last year's escrow analysis and see which one yours did, because that's $180 a year of found money or $180 a year going nowhere.
The second reason is control of the cash. An escrow account is a forced savings account that pays you nothing, and the servicer picks the size of the cushion. Paying the county yourself out of a line of credit means the money sits against your balance all year, cutting the interest you're charged every single day, and then leaves on November 15 in one piece. On a $6,000 annual bill held against an 8% line of credit for an average of six months, that's roughly $240 of interest you never paid, sitting on top of the $180 discount.
Insurance works the same way. The premium comes due once a year, you pay it off the line of credit, and plenty of carriers discount the annual payment against paying monthly.
The risk is exactly the one you'd expect. Nobody is going to remind you. Miss the property tax deadline and the county charges interest, and if it runs far enough the lender can force an escrow account back onto the loan or pay the taxes themselves and bill you. Miss the insurance premium and the lender buys a policy on the house for you and bills you for it, at several times what yours costs. So this move belongs to households that already run a monthly review and actually do it. If the ten-minute monthly review isn't a habit yet, build that first and come back to this.
Set it up so it can't be forgotten. Calendar reminders on October 1 and November 1. The county's online payment page bookmarked. And the money treated as a draw you owe back on a schedule, the same as any other chunk. Which bills belong on the line of credit sorts the ones that work from the ones that don't.