A standard home inspection is your foundation. Specialty services are how you build a business that earns significantly more per day without working significantly more hours. Each specialization covered here adds a revenue stream that attaches to inspections you are already running, requires its own certification and equipment, and serves a real need your clients have. Here is a detailed breakdown of each one.
Radon Testing
What it is
Radon is a colorless, odorless radioactive gas produced by uranium decay in soil. It seeps into buildings through foundation cracks, gaps, and permeable concrete. Radon is the second leading cause of lung cancer in the United States and cannot be detected without testing. Homes in parts of Oregon and Washington sit in elevated radon zones, making testing especially relevant in this market.
Certification requirements
Oregon and Washington do not currently require state-specific radon measurement certification, but national certification through the National Radon Proficiency Program (NRPP) or the National Radon Safety Board (NRSB) is the professional standard. These certifications require completing an approved course (typically 16 hours), passing an exam, and maintaining CEUs for renewal. NRPP and NRSB certifications are also required by many real estate transactions and lenders when a radon test result is used as part of a purchase negotiation.
Equipment costs
Passive charcoal canisters sent to a lab are the most affordable option. Kits cost $10 to $20 each, and labs charge $25 to $40 for analysis. Your client fee covers these costs and your markup is profit. Electronic continuous radon monitors like the CRM and Safety Siren Pro cost $150 to $400 each and can be reused across hundreds of jobs, giving you faster results and a more professional presentation. Most serious radon inspectors own two or three monitors to run parallel tests when needed.
Revenue potential
Radon testing fees run $125 to $175 in the Portland and Southwest Washington market. Time cost per job is minimal. Inspectors who mention radon at booking typically see 60 to 80 percent attachment rates. At 300 inspections per year with a 70 percent attachment rate, radon testing alone adds $26,000 to $37,000 in annual gross revenue.
Mold Testing
What it is
Mold testing involves collecting air samples or surface samples from areas of suspected mold growth and sending them to a certified lab for analysis. Results identify whether mold spores are present, the species, and the concentration. In the Pacific Northwest, where moisture is a near-constant concern, mold testing naturally attaches to many inspections where moisture findings prompt further investigation.
Certification requirements
Oregon and Washington do not require state licensing specifically for mold assessment. However, professional certifications from organizations like the American Council for Accredited Certification (ACAC) provide credibility and training. The Certified Microbial Investigator (CMI-ACAC) and Council-certified Mold Remediator designations are industry-recognized. At minimum, a course in mold sampling protocols and lab interpretation is essential before offering this service professionally.
Equipment costs
An air sampling pump runs $300 to $600. Sample cassettes cost $5 to $15 each. Lab analysis fees run $20 to $40 per sample. A standard mold test involving three to five samples (one outdoor control, two to four indoor) has a material cost of $75 to $150 per job. The pump is reused across all future jobs.
Revenue potential
Mold testing fees range from $200 to $500 per appointment depending on sample count. Unlike radon, which attaches to most jobs, mold testing attaches selectively when moisture findings suggest elevated risk. Inspectors using thermal imaging and moisture meters find more situations that justify mold testing, creating more natural add-on opportunities. Even at a 20 to 30 percent attachment rate, mold testing adds meaningful annual revenue.
Sewer Scope Inspection
What it is
A sewer scope sends a camera through the main sewer lateral from the home to the city main, evaluating pipe condition, flow, and any obstructions or damage. It is the only way to assess the underground sewer line before purchase. In older Portland and Vancouver neighborhoods, common findings include orangeburg pipe, deteriorated cast iron, root intrusion, and offset joints caused by soil movement.
Certification requirements
No specific state license is required in Oregon or Washington to perform residential sewer scope inspections as part of a home inspection service. However, professional training in camera operation, pipe identification, and defect recognition is essential. InterNACHI offers a sewer inspection course. Practicing on accessible lines before charging clients is strongly recommended. Some inspectors build relationships with plumbing companies that provide scoping services as a referral, which avoids equipment cost but reduces revenue margin significantly.
Equipment costs
A professional sewer camera setup capable of residential work runs $3,000 to $8,000. Entry-level units like the General Pipe Cleaners SeeSnake or RIDGID inspection cameras are widely used. Higher-end systems include self-leveling cameras, longer cable capacity for commercial work, and better recording systems. The equipment pays back quickly. At $175 per scope and 200 scopes per year, annual revenue from this service is $35,000 before expenses. Equipment payback at that volume happens in the first few months.
Revenue potential
Sewer scope fees run $150 to $250 in the Portland metro market. Attachment rates on homes built before 1980 can exceed 70 percent when the service is proactively recommended. At 300 inspections per year with a 50 percent attachment rate and a $175 fee, sewer scopes add $26,000 annually in gross revenue.
Septic System Inspection
What it is
Properties outside municipal sewer service areas use private septic systems. A septic inspection evaluates the tank, distribution box, and drain field for condition, capacity, and compliance. Failed septic systems are among the most expensive discoveries a buyer can make after closing. Replacement or repair costs frequently run $10,000 to $30,000 or more depending on the system and site conditions.
Certification and licensing requirements
This is the most regulated specialty on this list. In Oregon, performing a septic inspection as part of a real estate transaction involves working within the framework of Oregon DEQ and county environmental health requirements. Washington has similar oversight under DOH and county regulations. Many home inspectors who offer septic services do so through partnership with a licensed septic professional rather than holding their own license. That partnership model lets you offer the service and coordinate the appointment while the licensed partner performs the evaluation. You mark up appropriately or receive a referral fee.
Revenue potential
Septic inspection fees including a pump-out run $300 to $600 or more. This service is not relevant on every job but is essential on rural properties and homes outside city sewer service. Inspectors who serve areas like rural Clark County, the Willamette Valley foothills, or rural Washington communities will encounter these properties regularly. Even at lower volume, the per-job revenue is high.
Well Water Testing
What it is
Properties on private wells require water quality testing that municipal water connections do not. A well water test evaluates drinking water for bacteria (coliform and E. coli), nitrates, pH, hardness, and other contaminants depending on the panel ordered. Many lenders require well water testing for FHA, VA, and USDA loans, making this a mandatory service in rural transactions rather than just an optional add-on.
Certification requirements
In Oregon, water sampling for real estate purposes must be sent to an Oregon Health Authority certified laboratory. The sampling protocol matters for lab acceptance. In Washington, similar lab certification requirements apply. Most inspectors collect samples using a sterile kit provided by the lab, following the collection protocol precisely to avoid sample contamination that would invalidate results. No special license is required to collect samples, but you must use an approved lab and follow their collection procedures.
Revenue potential
Well water testing fees run $100 to $250 depending on the test panel. Expanded panels testing for more contaminants command higher fees. Like septic inspections, this service is location-specific but commands very high attachment rates on properties with private wells because buyers and lenders often require it. Per-job revenue is strong relative to the minimal time investment of sample collection.
How to Prioritize Which Specializations to Add First
If you are a new inspector deciding where to invest first, radon testing is the easiest entry point. Low equipment cost, quick certification, high attachment rate, and minimal time per job make it the best return on investment among all specialty services. Sewer scope is the highest-revenue individual service but requires meaningful equipment investment upfront.
Mold testing makes sense once you are using thermal imaging and moisture meters regularly, because those tools generate the findings that justify mold testing naturally. Septic and well are highly valuable in rural markets but not primary priorities if your territory is primarily urban and suburban.
For more on how specialty services build overall income, see Can You Make Six Figures as a Home Inspector? and What Add-On Services Make Home Inspectors the Most Money?