ADU Cost Segregation Study
A full engineering-based analysis of your accessory dwelling unit that reclassifies building components into 5-, 7-, or 15-year depreciation schedules, dramatically accelerating your deductions and boosting cash flow.
ADUs are one of the most overlooked opportunities for accelerated tax depreciation. Whether you've built a backyard cottage, garage conversion, or detached guest suite, Seneca Cost Segregation's engineering-based studies reclassify your ADU's components to unlock front-loaded deductions—turning 20–40% or more of your property costs into immediate, IRS-compliant tax savings.
Comprehensive cost segregation solutions designed to maximize tax savings for accessory dwelling unit owners across all 50 states.
A full engineering-based analysis of your accessory dwelling unit that reclassifies building components into 5-, 7-, or 15-year depreciation schedules, dramatically accelerating your deductions and boosting cash flow.
Already own your ADU? Claim all missed depreciation from the past 15 years in a single tax year using IRS Form 3115—no amended returns required, with the same rigorous engineering analysis.
A convenient 30–45 minute video-call inspection of your ADU eliminates the need for costly on-site visits, delivering faster turnaround in 2–3 weeks while keeping study costs affordable.
Every ADU cost segregation study includes Seneca's AuditDefense guarantee—comprehensive IRS audit support at no additional charge for as long as you own the property, backed by a potential study cost refund.
Post-study implementation support ensures your CPA can seamlessly integrate ADU depreciation schedules into your tax returns, with Seneca's team available to answer technical questions throughout the process.
Need your ADU cost segregation study completed before a tax deadline? Expedited service delivers fully engineered reports in as little as one week to meet your most urgent timing requirements.
We assess your ADU's eligibility, estimate your potential first-year tax savings, and walk you through expected ROI—completely free. Most ADU owners are surprised to learn how much accelerated depreciation they qualify for, even on smaller structures.
See how ADU and real estate property owners have unlocked significant tax savings with Seneca Cost Segregation.
"Dylan and his team at Seneca Cost Segregation are extremely knowledgeable. When I explored their website, it was clear they knew their stuff. It offered a very professional approach to cost segregation, backed by years of experience."
"We contacted Seneca for a Cost Seg Study and they went above and beyond. Their eagerness to help and province of info will blow you away."
"Extremely professional and efficient in their cost set analysis. Great communication and transparency. Will be using them going forward on all my properties."
"The tax savings achieved with Seneca Cost Segregation made a major impact on my bottom line. I wasn't aware it was a possibility until they brought the opportunity to me. Their insight and expertise are invaluable."
"We contacted Dylan for a cost seg study and he went above and beyond Not only will their pricing be the best price you will find, his eagerness to help and province info will blow you away"
"Their team was incredibly professional, prompt, and easy to work with."
"I couldn't be more pleased with the results. Their team was incredibly professional, prompt, and easy to work with. I achieved a highly favorable tax situation and recommend Seneca to anyone looking to maximize their tax benefits."
"Seamless experience with great results. Highly recommend!"
"I've referred multiple clients to Seneca, and each time they uncovered significant tax savings. Their team is fast, professional, and easy to work with. They've become a trusted extension of our tax strategy."
"Dylan and his team at Seneca Cost Segregation are extremely knowledgeable. When I explored their website, it was clear they knew their stuff. It offered a very professional approach to cost segregation, backed by years of experience."
"We contacted Seneca for a Cost Seg Study and they went above and beyond. Their eagerness to help and province of info will blow you away."
"Extremely professional and efficient in their cost set analysis. Great communication and transparency. Will be using them going forward on all my properties."
"The tax savings achieved with Seneca Cost Segregation made a major impact on my bottom line. I wasn't aware it was a possibility until they brought the opportunity to me. Their insight and expertise are invaluable."
"We contacted Dylan for a cost seg study and he went above and beyond Not only will their pricing be the best price you will find, his eagerness to help and province info will blow you away"
"Their team was incredibly professional, prompt, and easy to work with."
"I couldn't be more pleased with the results. Their team was incredibly professional, prompt, and easy to work with. I achieved a highly favorable tax situation and recommend Seneca to anyone looking to maximize their tax benefits."
"Seamless experience with great results. Highly recommend!"
"I've referred multiple clients to Seneca, and each time they uncovered significant tax savings. Their team is fast, professional, and easy to work with. They've become a trusted extension of our tax strategy."
"Dylan and his team at Seneca Cost Segregation are extremely knowledgeable. When I explored their website, it was clear they knew their stuff. It offered a very professional approach to cost segregation, backed by years of experience."
"We contacted Seneca for a Cost Seg Study and they went above and beyond. Their eagerness to help and province of info will blow you away."
"Extremely professional and efficient in their cost set analysis. Great communication and transparency. Will be using them going forward on all my properties."
"The tax savings achieved with Seneca Cost Segregation made a major impact on my bottom line. I wasn't aware it was a possibility until they brought the opportunity to me. Their insight and expertise are invaluable."
"We contacted Dylan for a cost seg study and he went above and beyond Not only will their pricing be the best price you will find, his eagerness to help and province info will blow you away"
"Their team was incredibly professional, prompt, and easy to work with."
"I couldn't be more pleased with the results. Their team was incredibly professional, prompt, and easy to work with. I achieved a highly favorable tax situation and recommend Seneca to anyone looking to maximize their tax benefits."
"Seamless experience with great results. Highly recommend!"
"I've referred multiple clients to Seneca, and each time they uncovered significant tax savings. Their team is fast, professional, and easy to work with. They've become a trusted extension of our tax strategy."
We combine engineering precision, real estate investor expertise, and a client-first approach to deliver ADU cost segregation studies that stand up to IRS scrutiny and maximize your returns.
Every ADU study is built on rigorous engineering methodology and proprietary technology, ensuring IRS-compliant, audit-ready results.
Our founders are real estate investors themselves—they understand ADU ownership challenges and structure studies to maximize your after-tax cash flow.
With engineers deployed across all 50 states and virtual tours available anywhere, we serve ADU owners in every market, from dense urban areas to rural properties.
Every ADU study includes lifetime IRS audit defense at no extra cost—backed by a money-back guarantee if the study has a material issue.
Real estate investors and engineers committed to maximizing your ADU tax savings.
Co-Founder and CEO
Dylan Scandalios is an active investor in multi-family properties across the Pacific Northwest and a recognized Cost Segregation Expert. Before co-founding Seneca Cost Segregation, Dylan closed millions of dollars in business for both public and private companies along the West Coast, giving him a sharp understanding of real estate finance and investor priorities. As CEO, Dylan leads the firm's mission to make engineering-based cost segregation accessible and affordable for every property owner—including ADU investors. Under his leadership, Seneca has helped real estate investors save millions on their taxes, completed over 10,200 studies nationwide, and achieved a 95% client referral rate. Dylan's investor-first perspective ensures every ADU study is structured to deliver maximum, real-world tax impact.
Co-Founder
Paul Spies brings a rare combination of military discipline and hands-on real estate expertise to Seneca Cost Segregation. A Marine Corps Sergeant, Paul has over 8 years of experience in real estate construction—successfully flipping over 150 homes in just 4 years and leading ground-up multi-family projects from conception to completion. As a Principal Broker and Licensed Contractor, Paul has a firsthand understanding of how properties are built and how their components should be classified for maximum depreciation benefit. Having personally used cost segregation since 2018, he co-founded Seneca to bring the same competitive tax advantage he experienced to other investors at an affordable, on-time delivery. Paul's construction knowledge is especially valuable when analyzing ADUs, where component classification requires precision and building expertise.
Yes, absolutely. Accessory dwelling units—including detached cottages, garage conversions, basement apartments, and guest suites—are eligible for cost segregation studies just like larger rental properties. Our engineering team identifies and reclassifies depreciable components of your ADU into 5-, 7-, or 15-year categories, accelerating deductions that would otherwise be spread over 27.5 years.
Talk to one of our cost segregation experts for a free consultation and personalized savings estimate.
Seneca Cost Segregation serves ADU owners across all 50 states with virtual and on-site study options.
All 50 States
Service Area
10,200+
Studies Completed
95%
Client Referral Rate
We serve ADU owners in all 50 states—virtually or on-site. Let's confirm coverage and get started.
Certified Cost Segregation Professional designation from ASCSP
Perfect five-star rating from satisfied clients nationwide
Proudly veteran-owned, delivering disciplined and reliable service
Tell us about your accessory dwelling unit and we'll provide a no-obligation savings estimate and ROI analysis—typically within one business day. Our team is ready to help you keep more of what you've earned.
For immediate assistance, feel free to give us a direct call at +1 530-797-6539 You can also send us a quick email at info@senecacostseg.com
For immediate assistance, feel free to give us a direct call at +1 530-797-6539 You can also send us a quick email at info@senecacostseg.com