A few minutes into almost every phone call, we get the same question: so when does the county come out to look at the house? Some people ask it casually. Others have been sitting on a grievance for years because of it, and a few have told us outright that they'd rather keep overpaying than let an inspector into the kitchen.
Nobody comes to the house. That's the whole answer, and it's the county's answer, not ours.
What actually happens
A grievance is a written application. You file it with the Assessment Review Commission between early January and the first business day of March, and that filing is the entire case. A staff appraiser at ARC pulls what the county already has on your property, sets it next to recent sales of similar homes, and works from paper at a desk in Mineola. The commission's own FAQ asks the question head-on, "Must I appear in person?", and prints the answer: no.
If you grew up upstate you may remember Grievance Day, where homeowners line up and make their case to the assessors face to face. Nassau doesn't hold one. There's no room to show up to even if you wanted to.
You don't need to arrive with an appraisal either. ARC can't require you to hire an appraiser or to dig up comparable sales on your own. And if you'd feel better talking to a person, you can ask for a conference, over the phone if both sides agree. It happens only if you ask for it.
The visit people are half-remembering
The county does send people to houses. Different office, different reason. Pull a permit, add a dormer, finish the basement, and the Department of Assessment may send someone to record what changed, because new construction sits outside the 6 percent cap that limits how fast an assessment can rise. That visit runs on the county's calendar. Filing a grievance doesn't cause it, and skipping a grievance doesn't prevent it.
If ARC denies you and you push on to Small Claims Assessment Review, there is finally a hearing, in a courthouse, and you can send a representative instead of going yourself.
After filing, mostly you wait. Determinations arrive by mail when the final roll comes out, sometimes fifteen months after you sent the form in.
Don't take our word for any of it. ARC's Rules of Procedure and its FAQ say all of this in the county's own language.