How to Adjust Land Comps for Access, Utilities, Zoning, and Buildability

Comparable sales are the foundation of almost every vacant land value estimate. The problem is that most comp mistakes are not arithmetic mistakes — they are similarity mistakes. This guide walks through how to decide whether a sale is genuinely comparable before you enter it into the Vacant Land Value Estimator.

How do you adjust land comps?

Start by comparing each sale to the subject property's location, acreage, legal access, utilities, zoning, usable area, water and wastewater options, flood risk, physical constraints, and development potential. Exclude sales that are fundamentally different. When differences remain but cannot be reliably quantified, document them and use a wider preliminary value range rather than inventing a precise adjustment.

A nearby sale is not automatically a good comp, and price per acre alone does not make two parcels comparable.

1. The calculation can be right while the comp is wrong

The math behind a comp is simple:

Comp price per acre = closed sale price ÷ acreage

That arithmetic can be completely accurate and still produce a misleading estimate if the comp is not sufficiently similar to the subject property.

Consider two parcels:

• Subject property: 10 acres
• Comp: 10 acres
• Same general area
• The comp has paved legal access, power, water, and usable terrain
• The subject property has unresolved access, no confirmed utilities, and substantial slope

Identical acreage does not make these properties equal. A buyer for the comp was purchasing a usable, serviceable building site. A buyer for the subject property is purchasing unanswered questions. Dividing price by acreage does nothing to reconcile that difference — it just hides it behind a clean-looking number.

2. Start with the strongest basic similarities

Before you look at anything subtle, screen for the basics:

• Same county or a genuinely comparable market area
• Similar acreage band
• Similar sale date
• Closed sale rather than an active listing
• Similar intended use
• Similar zoning
• Similar development stage
• Similar physical characteristics

Acreage band deserves special attention. A one-acre homesite, a ten-acre rural tract, and a forty-acre agricultural property attract different buyers, carry different per-acre pricing behavior, and are financed differently. Averaging them together because they are nearby produces a per-acre figure that describes none of them. Group comps by acreage class first, then compare inside the group. For the sourcing workflow, see how to find land comps.

3. Compare legal and physical access

Access is the difference most often missed and most likely to matter. Compare:

• Recorded legal access
• Public-road frontage
• Private-road rights
• Easements
• Road condition
• Seasonal access
• Driveway feasibility
• Emergency-access requirements

A parcel with paved public access is generally not a clean comp for land with unresolved or physically difficult access. The gap is not only cost — it is time, approval risk, and whether a lender or title company will treat the parcel as normal. Work through how to check access on land and legal vs. physical access on vacant land for both sides of that question.

4. Compare utilities and connection feasibility

For each comp and for the subject property, look at:

• Power
• Water
• Sewer
• Septic feasibility
• Gas
• Telecommunications
• Distance to infrastructure
• Available capacity
• Easements
• Extension requirements
• Connection costs

"Utilities nearby" is not the same as utilities available, approved, or affordable to connect. A line across the road can still mean an easement you do not have, a capacity constraint, or an extension estimate that changes the deal.

Useful references: how to check utilities on vacant land, how to verify power availability and connection costs before buying land, how to verify water availability before buying land, how to verify sewer availability before buying land, and septic feasibility and perc tests.

5. Compare zoning and allowed use

Zoning defines what the buyer was actually buying. Compare:

• Allowed uses
• Minimum lot size
• Density
• Frontage
• Setbacks
• Overlays
• Conditional-use requirements
• Subdivision potential
• Existing nonconforming status

A parcel that already allows the intended use is not a clean comp for one that requires rezoning, a variance, or another unapproved entitlement. Entitlement risk is priced by buyers, and it is priced differently in every jurisdiction. See how to verify zoning on land before treating a listing's zoning label as fact.

6. Compare total acreage with usable acreage

Headline acreage is the number in the listing. Usable acreage is the number that drives value. Land can be effectively removed from use by:

• Steep slopes
• Floodplain
• Wetlands
• Drainage
• Waterway setbacks
• Easements
• Rights-of-way
• Irregular shape
• Poor soils
• Unusable remnants
• Required open space

Ten acres with four usable acres is not automatically comparable to ten acres with nine usable acres. Pull the parcel and constraint layers through the County GIS Finder and record what you see for both properties, with the date and source.

7. Compare water and wastewater feasibility

Water and wastewater decide whether anything can be built, and they vary parcel by parcel. Compare:

• Public water
• Well feasibility
• Water rights where applicable
• Public sewer
• Septic feasibility
• Perc testing
• Required wastewater area
• Reserve drainfield area
• Connection moratoriums
• Capacity constraints

A comp with an approved system or a confirmed public connection reflects a resolved question. If the subject property's wastewater path is unknown, that uncertainty affects whether the comp supports the subject property's preliminary value at all — not just by how much.

8. Compare flood risk and physical constraints

Compare mapped and observed conditions:

• FEMA flood zones
• Local flood studies
• Drainage
• Wetlands
• Erosion
• Slope
• Geotechnical concerns
• Wildfire or emergency-access constraints where relevant

No single mapped layer determines value or buildability. A flood-zone designation is a prompt to investigate elevation, engineering, insurance, and usable-area questions — not a verdict. Read the flood zone guides alongside how to tell if land is buildable so mapped risk is interpreted in context.

9. Compare development potential

Development potential is where comps most often diverge. Compare:

• One homesite versus multiple potential lots
• Existing approvals
• Preliminary concepts versus recorded plats
• Utility capacity
• Road and access requirements
• Required engineering
• Builder-ready versus uninvestigated land

Possible is not the same as approved. A subdivided or builder-ready parcel is not automatically a clean comp for land whose development assumptions remain unverified. For how value moves across those stages, see what land is worth as raw, builder-ready, and subdivided lots and why two pieces of land have different values.

10. Decide whether to include, question, or exclude each comp

Give every candidate sale one of three statuses.

Include

Use when the sale is reasonably similar in location, acreage, access, utilities, zoning, usable area, and intended use. These are the comps that belong in your preliminary range.

Question

Use when the sale may still be informative but contains material differences or unverified assumptions. Keep it, document the differences, and do not present the resulting estimate as precise.

Exclude

Use when the property is fundamentally different, such as:

• Different market
• Different acreage class
• Different allowed use
• Improved rather than vacant land
• Builder-ready versus uninvestigated
• Confirmed utilities versus no realistic service path
• Legal access versus unresolved access
• Primarily usable land versus heavily constrained land

Excluding a comp is not a loss of data. It prevents a clean-looking average from carrying a difference you already know is material.

11. Why universal percentage adjustments are dangerous

This guide deliberately does not tell you to:

• Subtract 10% for no power
• Add 15% for paved access
• Subtract 20% for floodplain
• Add a fixed amount for subdivision potential

Those shortcuts feel precise and are not. The market effect of any single factor depends on:

• Location
• Buyer expectations
• Development costs
• Local supply
• Intended use
• Severity of the constraint
• Whether the issue can be solved
• Time and approval risk

The same missing power line can be a minor cost in one market and a deal-ending problem two counties away. When you need a formal valuation or a defensible adjustment — for lending, litigation, partnership, tax, or estate purposes — engage a qualified local appraiser, broker, or other appropriate professional.

12. Use the LandGauge estimator responsibly

A practical workflow:

1. Find three to five reasonably comparable closed sales.
2. Calculate each comp's price per acre.
3. Exclude fundamentally unsuitable sales.
4. Document material differences.
5. Enter the remaining comps into the Vacant Land Value Estimator.
6. Review the low, median, and high preliminary values.
7. Treat the range as a starting point.
8. Verify the assumptions that could change it.

For the wider valuation context, see how to estimate vacant land value and how much vacant land is worth. All of these live in the Land Value & Comps guides.

If the search never produces enough similar sales in the first place, see what to do when you cannot find enough usable comps.

13. Document the comparison in LandGauge

A comp set is only as durable as the notes behind it. LandGauge helps you organize:

• Comp source
• Closed-sale information
• Acreage
• Price per acre
• Access observations
• Utility information
• Zoning
• Usable acreage
• Buildability questions
• Verified answers
• Assumptions
• Remaining questions
• Sources and dates
• Next actions

Mark every field with the status that reflects reality: Verified, Assumed, Still Needs Verification, or Not Applicable. That single habit is what keeps a preliminary range honest three weeks later when someone asks where the number came from.

Investigate. Verify. Decide. Start a first pass in the Quick Analyzer and work the open items with the Land Due Diligence Checklist.

Comp comparison worksheet

Fill one column per candidate sale. This is a working reference, not a scoring system.

Build a Preliminary Range From Better Comps

Once you have three to five reasonably comparable closed sales, enter them into the LandGauge Vacant Land Value Estimator. The result is a preliminary range—not an appraisal—and is only as reliable as the comps and assumptions behind it.

• [Use the Vacant Land Value Estimator](/vacant-land-value-estimator)
• Analyze the Complete Land Deal

LandGauge is a research and underwriting workspace. It is not an appraisal, broker price opinion, legal opinion, engineering opinion, survey, or guarantee of market value, and it does not provide legal, tax, lending, or investment advice. Verify each item with the appropriate county department, utility provider, and qualified local professionals.