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Error fixing·6 min read

The cost approach & site value: the #1 avoidable Fatal

The cost-approach → site-value conditional chain causes more avoidable UCDP rejections than almost anything else. Here is the chain, spelled out.

In this guide
Rules coveredUAD1229UAD1231

Ask the copilot about this guide — it has read the whole hub and cites what it uses.

When you indicate the cost approach was used, a set of dependent fields becomes required — most notably the estimated site value. The logic is conditional, so it is invisible until you trip it, and it is a frequent cause of a bounced submission.

UAD1229FatalField 4.105Rule details →
Rule logic
If CostApproachIndicator = "true", or (CostApproachIndicator = "false" and SiteValueIndicator = "true") and SiteEstimatedValueAmount is not provided
Fix
Provide SiteEstimatedValueAmount whenever the cost approach is used or site value is indicated.
Seen in a sample
$284,000 in Single-family + ADU (SF3)
UAD1231WarningField 4.106Rule details →
Rule logic
If CostApproachIndicator = "true", or (CostApproachIndicator = "false" and SiteValueIndicator = "true") and SiteValuationMethodType is not provided
Fix
Provide the site valuation method alongside the amount. This is a Warning rather than a hard stop, but reviewers will still flag it.
Seen in a sample
SalesComparison in Single-family + ADU (SF3)

How to stay clean

  • Decide the cost approach question early — it changes what is required.
  • If cost approach = true, fill site value amount AND method together.
  • Validate before submitting so the conditional chain is checked for you.

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