In a lot of jurisdictions I work in, a 120 sq ft prefab shed gets flagged by aerial imagery and booked as an “improvement,” nudging assessed value by $3,000–$8,000 and bumping the tax bill unless you protest. Keep receipts and photos to show it’s movable or has low contributory value at valuation review to reduce liability; general info only — consult a qualified attorney for specific cases.
Had a 10x12 on skids get flagged; I got the bump rolled back by showing photos of the 4x4 skids, no anchors, no utilities, and the delivery invoice — “no slab, no utilities” seems to click. Caveat: pour a pad or bolt it down and many assessors treat it as real property, so check your property record/GIS and, for specifics, ask a local pro or a qualified attorney; think of it like a big cooler on the lawn, not an addition.
Always keep your docs handy, especially if you wanna protest that bump.