Home Inspection Add-On Services: Radon, Sewer Scopes, WDO and Mold Pricing

A standard home inspection has a ceiling: there are only so many inspections you can do in a week. Ancillary services raise the value of each job instead. Adding radon testing, a sewer scope or a termite inspection to a fraction of your jobs can raise your average revenue per inspection by $100 to $300 or more, while helping clients make better decisions. This guide covers the common add-ons, their prices, licensing and how to calculate equipment payback.

Prices are illustrative ranges as of 2026. Verify local market rates and licensing requirements.

Common add-ons compared

Radon testing

Radon is a naturally occurring radioactive gas and a leading cause of lung cancer among non-smokers, according to the EPA. Many buyers want testing, especially in areas with elevated radon. Key points:

• Use continuous radon monitors or approved test devices, and follow the testing protocols your state or credentialing body requires.
• Tests usually run at least 48 hours under closed-house conditions, so plan drop-off and pick-up trips.
• Check your state's licensing or certification rules; many states require them.
• Explain results clearly and refer clients to EPA guidance and qualified mitigation contractors when levels are elevated.

Sewer scopes

A camera run through the main sewer line can find roots, cracks, offsets, bellies and collapsed pipe. Repairs can cost thousands, which makes sewer scopes valuable on older homes and homes with mature trees. Learn to identify pipe materials and common defects, record video for the client, and recommend evaluation by a plumbing or sewer contractor when you find problems. Be careful with access: only use cleanouts you can open safely, and do not remove toilets unless your agreement and training cover it.

Wood-destroying organism inspections

Lenders and buyers in many regions require WDO or termite inspections, often on state-specific forms. These usually require a pest control license or certification. Some inspectors get licensed; others partner with a local pest control company and coordinate scheduling.

Mold, lead and asbestos

These services can be valuable but carry more regulation and liability. Some states license mold assessors, and lead and asbestos work generally requires specific certification. Confirm your E&O insurance covers each service before offering it, since many policies exclude mold or environmental testing unless added.

Equipment payback math

Sewer scope: camera and training cost $5,000. You charge $225 per scope and spend about $25 per job on extra time and wear.

$5,000 ÷ $200 = 25 sewer scopes to pay back

At a 25 percent attach rate on 300 inspections a year, that is 75 scopes. The camera pays for itself in about four months.

Radon: two continuous monitors at $1,000 each plus $500 in training and certification = $2,500. At $175 per test with $25 in costs (calibration and the extra trip):

$2,500 ÷ $150 ≈ 17 tests to pay back

How add-ons change annual revenue

On 300 inspections, that is about $140 more per inspection on average, without adding a single new client.

Matching add-ons to your market

Choose services based on local housing and risk, not national trends:

• Older neighborhoods with mature trees: sewer scopes
• Areas with elevated radon: radon testing, using EPA and state radon maps as a starting point
• Termite-prone regions: WDO inspections, through your own license or a partner
• Rural areas: well water testing and septic evaluation
• Coastal and storm regions: wind mitigation and 4-point inspections where insurers use them
• Pool-heavy markets: pool and spa inspections

Ask local agents which services buyers request most. Their answers tell you where demand already exists.

Selling add-ons without pressure

• Offer them at booking. List add-ons in your online scheduler with a short explanation of why each matters.
• Bundle them. A "complete package" with inspection, radon and sewer scope at a modest discount simplifies the decision.
• Educate agents. Agents who understand why a sewer scope matters on a 60-year-old home will recommend it.
• Explain the risk honestly, using local information and official sources. Never use fear tactics.

Building add-on services step by step

• ☐ Choose one add-on that fits your area's housing stock and risks
• ☐ Confirm licensing or certification requirements
• ☐ Confirm your E&O covers it, or add an endorsement
• ☐ Complete training
• ☐ Buy equipment and practise on your own or friends' homes
• ☐ Update your agreement and report templates
• ☐ Add it to your online scheduler with clear pricing
• ☐ Track attach rate monthly

Scheduling add-ons around the transaction

Real estate timelines are tight. Most buyers have an inspection contingency period measured in days, and add-on results must arrive in time for negotiations. Build your schedule around that:

• Radon: place monitors at or before the inspection and confirm the pick-up time so results are ready within the contingency window. Explain closed-house conditions to the seller's agent in writing.
• Sewer scope: perform it during the inspection when possible; locate the cleanout early and confirm water is running in the home.
• WDO: coordinate with the lender's form and deadline requirements.
• Lab-based tests: check the lab's turnaround time before promising a delivery date.

Put a short "what to expect" note in your booking confirmation for each add-on so clients and agents know timing in advance.

Reporting add-on results clearly

Include add-on results in the main report or as a clearly linked addendum. For each one, state what was tested, how, the result, any limitations and the recommended next step. Sewer scope reports should include video links and timestamps for defects. Radon reports should show the average result and reference EPA guidance on action levels. Clear add-on reports make agents comfortable recommending them again.

Common mistakes

1. Offering services without the required license.
2. Insurance gaps for environmental or ancillary services.
3. Buying every tool at once before knowing demand.
4. Poor scheduling, such as radon tests that cannot finish before the inspection contingency deadline.
5. Overselling services that do not fit the property.

Questions readers ask

Should I include thermal imaging in every inspection?

Many inspectors include thermal imaging as a differentiator rather than charging separately, while others offer it as an add-on. If you include it, explain its limits in your agreement: thermal cameras show temperature differences, not moisture or defects directly, and findings need interpretation.

Can I subcontract add-on services?

Yes, many inspectors partner with licensed pest control companies, radon professionals or labs. Make the relationship clear to clients, confirm the partner's licensing and insurance, and coordinate scheduling so results arrive within the contingency period.

Your next step

Look at your last 20 inspections and ask which add-on would have helped those clients most. Check the licensing rules for that service and get one equipment quote this week.

The full guide, Starting a Home Inspection Business, covers licensing, training, insurance, tools, pricing, reports, ancillary services, agent relationships and a launch plan, for $0.99.