Termite Inspection Frequency Calculator
Estimate how frequently you should schedule professional termite inspections based on your property's risk profile, construction type, prior history, and geographic termite pressure.
Formula
Risk Score = Climate Factor × Construction Factor × Age Factor × History Factor × Moisture Factor × Treatment Factor
Raw Interval (months) = 24 ÷ Risk Score
Recommended Interval = Raw Interval clamped to [3, 24] months, then snapped to the nearest standard interval: 3, 4, 6, 9, 12, 18, or 24 months.
Each factor is a dimensionless multiplier ≥ 1.0 (except the treatment discount factor which can be < 1.0). A higher combined score compresses the inspection interval, reflecting elevated risk.
Assumptions & References
- The industry baseline of once per year (12 months) is widely recommended for moderate-risk properties; this calculator adjusts that baseline up or down based on compounding risk factors.
- Climate zones are derived from the USDA termite infestation probability map and the National Pest Management Association (NPMA) regional risk classifications.
- Construction type weights reflect that wood-to-soil contact and crawl spaces are the primary structural risk factors per the International Residential Code (IRC) Section R318.
- Age factor increases with structure age because older buildings accumulate hidden entry points, wood degradation, and gaps in original chemical barriers.
- Prior history multipliers are based on recurrence data: treated properties have a 20–40% recurrence rate within 5 years without ongoing monitoring (University of Florida IFAS Extension).
- Moisture factor reflects that subterranean termites require moisture to survive; damp wood and poor drainage are the leading conducive conditions (EPA Termite Prevention Guidelines).
- Treatment discount applies only when an active, professionally maintained bait or chemical barrier system is in place; expired treatments receive no discount.
- Cost estimates ($75–$150 per inspection) reflect typical U.S. market rates for a standard single-family home inspection; prices vary by region and property size.
- This calculator provides general guidance only. Always consult a licensed pest management professional (PMP) for a site-specific assessment.