What Is a WDO Inspection?

WDO Stands for Wood Destroying Organism

A WDO inspection (Wood Destroying Organism inspection) is a licensed, systematic examination of a structure for evidence of termites, wood-boring beetles, wood-decay fungi (dry rot), and the conditions that make each of these likely to develop. The "WDO" term encompasses all of these organisms because they all damage the structural integrity of wood in a building.

Why WDO Inspections Are Required for North Bay Real Estate

In California, most mortgage lenders require a current WDO report as a condition of financing. Lenders require this documentation because: (1) termites and wood decay are endemic throughout the North Bay and can significantly affect the structural value of the property they are lending against; (2) lenders need to know that the collateral for their loan is structurally sound; and (3) California law requires disclosure of known material defects, and a WDO inspection is the standard mechanism for documenting pest and wood-decay status.

What Is Inspected

A complete WDO inspection covers: the exterior perimeter (foundation walls, exterior wood surfaces, crawl space vents, roofline); the crawl space (sill plates, floor joists, subfloor, posts, beams, moisture conditions); the attic (roof framing, top plates); and the interior (baseboards, window sills, under sinks, visible wood surfaces). All findings are mapped on a property diagram included in the report.

Understanding Section 1 and Section 2

California WDO reports are structured in two sections:

• Section 1: Active infestations and conditions requiring correction. Active termite infestation, active wood-decay fungus, current wood-boring beetle activity. Most North Bay lenders require all Section 1 items to be corrected before funding
• Section 2: Conditions conducive to future pest activity. Wood-soil contact, inadequate crawl space ventilation, moisture-related conditions. Correction is recommended but typically not lender-required
• "Further inspection required": areas the inspector could not fully assess due to limited access — noted on the report and typically requiring additional inspection to determine extent

WDO vs. Home Inspection — What Is the Difference?

A home inspection is a broad assessment of all major systems (plumbing, electrical, HVAC, structural, roof). A WDO inspection is a specialized examination focused exclusively on wood-destroying organisms and the conditions associated with them. Most North Bay real estate transactions involve both — they are complementary, not duplicative. Home inspectors note pest-related conditions they observe but do not issue the licensed WDO report that lenders require.

Frequently Asked Questions