Which Home Inspection Add-Ons Are Worth the Cost?
The standard home inspection is a visual assessment of accessible components. Specialty tests provide information the standard inspection cannot. Here is when each major add-on is worth adding.
Radon Testing: $125 to $225
Radon is a colorless, odorless radioactive gas that seeps from soil and rock into homes through foundation cracks and gaps. It is the second-leading cause of lung cancer in the US after smoking. The EPA recommends radon testing for all homes and recommends mitigation when levels exceed 4 pCi/L. Short-term radon tests (placed for 48 to 96 hours) are available as an add-on to home inspections. Testing is most important in geographic areas with elevated radon potential (Upper Midwest, Appalachia, Rocky Mountain region), in homes with basements or crawlspaces, and for homes with mechanically ventilated slabs. (For more on this, see Hidden Costs of Home Inspections.) The EPA identifies radon as the second leading cause of lung cancer and recommends testing any home, new or old.
Termite Inspection: $100 to $175
A termite inspection by a licensed pest inspector examines the home for signs of active termite infestation, past damage, and conducive conditions. Some states require a WDO (Wood Destroying Organism) report for real estate transactions. Even where not required: a termite inspection is strongly recommended in the South, Southeast, Gulf Coast, and any region with significant subterranean termite pressure. A termite inspection is one of the most cost-effective add-ons relative to the potential financial consequences of an undetected infestation. (For more on this, see How Much Does a Home Inspection Cost?.)
Mold Testing: $250 to $400
Air sampling or surface sampling for mold provides laboratory identification of mold species present and spore concentration levels. Recommended when the inspection reveals moisture intrusion evidence, visible biological growth in walls or HVAC systems, musty odors, or any history of flooding or water damage. Mold testing is more expensive than other add-ons and may not be necessary for homes without moisture concerns.
Sewer Scope: $125 to $300
A camera is run through the main sewer line from the cleanout access to the municipal connection, identifying root intrusion, offset joints, cracks, and blockages. Strongly recommended for homes over 20 to 30 years old, homes with large trees near the sewer line, and homes where the sewer line history is unknown. A compromised sewer line requires repair or replacement at $3,000 to $15,000+ making the sewer scope one of the highest-ROI due diligence investments for older properties.
Working With a Contractor on This Project
Getting the right outcome on any home services project starts before the work begins. A few consistent practices make the difference between a smooth project and a frustrating one.
Get at least two or three quotes. A single quote gives you no basis for comparison. Two or three quotes reveal the market rate for the work, expose scope differences between bidders, and let you assess contractor communication quality before any commitment is made. The lowest bid is not automatically the best value if the scope is thin or the materials are underspecified.
Ask for licenses and insurance before work starts. Verify current general liability insurance and, for any work involving workers on your property, workers compensation coverage. Licensing requirements vary by state and trade; confirm the specific requirements in your jurisdiction. A licensed contractor who carries appropriate insurance protects both parties if something goes wrong during the project.
Get the scope in writing. A written proposal that specifies materials, labor scope, timeline, what is included (permits, cleanup, disposal), and warranty terms is the foundation of a professional engagement. Verbal agreements on any of these points invite misunderstanding. For any project over $500, written scope is non-negotiable.
Clarify the payment schedule upfront. A reasonable payment schedule ties major payments to project milestones: a deposit at signing, a payment at material delivery or project start, and a final payment at completion after a walkthrough confirms satisfaction. A contractor who requires full payment upfront before work begins is a red flag in any trade.
Making a Confident Decision
The information in this article is designed to help you ask better questions of the professionals you work with, evaluate their answers with more confidence, and understand the decisions involved in this type of home services project. It is not a substitute for professional assessment of your specific home. (For more on this, see Questions to Ask Before Hiring a Home Inspector.)
Every home is different. Roof slopes, local weather, tree exposure, soil conditions, and existing system condition all affect what the right solution is for your specific situation. The general principles here apply broadly, but a professional who assesses your home in person will give you guidance that accounts for the details that general articles cannot.
When you are ready to move forward, getting at least two or three quotes from licensed, insured, local contractors is the most important practical step. It lets you compare approaches, assess contractor quality, and confirm that the solution proposed matches your specific situation and budget.
Cost figures on this page were checked against published pricing on August 26, 2026. How we source cost data.