What Is Plottage
Plottage is the increase in combined land value that results from merging two or more adjacent parcels into a single larger parcel. A property owner with two 5,000-square-foot lots valued at $100,000 each might find that combining them into one 10,000-square-foot parcel creates a value of $225,000 because the larger unified site becomes more developable or marketable than the sum of its separate parts.
Why Assessors Apply Plottage
Assessors use plottage adjustments when calculating assessed values because the combination of parcels genuinely increases utility and market potential. This creates a critical issue in property tax assessment appeals: if your county assessor applies a plottage adjustment to your combined parcels, you must challenge it with evidence that the adjustment is excessive or unsupported.
In assessment hearings before a board of review, you can argue that comparable sales do not support the plottage premium claimed. For example, if an assessor adds a 20% plottage adjustment but recent comparable sales of combined parcels in your area show only a 10% premium, you have concrete grounds to reduce the assessment.
Plottage in Appraisals and Assessments
Appraisers calculate plottage by comparing the per-unit land value of combined parcels against separately valued parcels. If individual 1-acre parcels sell for $50,000 each, but a 2-acre combined parcel sells for $115,000, the $15,000 difference represents plottage value. Most assessment ratios (the relationship between assessed value and market value) assume plottage premiums of 5% to 25% depending on zoning, location, and development potential.
In your appeal, request the assessor's plottage calculation and comparable sale analysis. Many assessors apply a standard percentage without conducting sales comparison. Challenge this by presenting actual market data showing what combined parcels in your area have actually sold for recently.
Assembly Restrictions and Defensibility
Plottage only exists if the parcels can legally and practically be assembled. If deed restrictions, easements, or zoning limitations prevent true assemblage, the plottage adjustment is indefensible. Similarly, if market conditions show no buyer interest in combined parcels (because of access issues, environmental constraints, or utility limitations), comparable sales will not support the adjustment.
Common Questions
- Can I reduce my assessment by arguing my parcels should not be combined? Yes, if you hold separate deed records and they serve different purposes (residential rental vs. commercial storage, for example), you can argue at a board of review hearing that no true assemblage benefit exists and the plottage adjustment should be removed entirely.
- What comparable sales should I gather? Find recent sales of combined parcels similar in size, zoning, and location to yours. Sales data from your county assessor's records, MLS listings, and commercial brokers typically cover the past 12 to 24 months. If you cannot find comparable combined parcels, this strengthens your case that plottage does not apply in your market.
- Does plottage apply to all combined parcels? No. Plottage applies only where assemblage creates measurable added value. Corner lots zoned for commercial development may show 30% plottage, while rural parcels combined for agricultural use may show none. The assessor must justify the specific percentage applied to your property.