05/28/2026
The mortgage payment on your closing disclosure was built on the previous owner's tax bill — not yours. That's the part nobody explains. Property taxes funded 69.4% of Waltham's FY2018 budget, and the average single-family bill back then was $4,101 after the residential exemption. Values have climbed a lot since, and assessments follow. If the seller held the home for 10+ years at a stale assessed value, your escrow can jump by hundreds a month once the city catches up to what you actually paid.
Comment the Waltham neighborhood you're shopping and I'll tell you how big the assessment gap usually runs there.