Contractor Tax Deductions: What Your Bookkeeper Should Be Catching

Every year around February, I get calls from contractors who just got their tax bill and are in shock. They ran a profitable business — $3M, $5M, sometimes $10M in revenue — and somehow owe six figures to the IRS because nobody was tracking their deductions properly throughout the year. Not because the deductions don’t exist. Because nobody was paying attention.

This isn’t a tax advice article — I’m not a CPA, and your tax situation depends on your entity structure, state, and a dozen other variables. What this is: a financial operations checklist. These are the deduction categories that, across hundreds of home services P&Ls I’ve reviewed, are most commonly missed, under-documented, or miscategorized. If your bookkeeper isn’t actively tracking these throughout the year, you’re almost certainly overpaying.

The Problem: Tax Deductions Are a Bookkeeping Problem, Not a Tax Problem

Most contractors think tax planning happens in January when their CPA starts preparing the return. It doesn’t. Tax planning happens every single month when your bookkeeper categorizes transactions, reconciles accounts, and maintains your chart of accounts. By the time your CPA sees the numbers, they can only work with what’s been documented. If expenses were miscategorized, lumped together, or never recorded, those deductions are gone — your CPA can’t retroactively find what wasn’t tracked.

The contractors who pay the least in taxes (legally) aren’t doing anything exotic. They just have clean books. Every expense is categorized correctly. Every receipt is documented. Every vehicle mile is logged. Their CPA gets a clean P&L in January and can maximize every legitimate deduction because the data is there. The ones who overpay are the contractors whose books are a mess — expenses dumped into “miscellaneous,” personal and business charges mixed on one credit card, no mileage log, and half the receipts missing.

This is fundamentally a bookkeeping discipline problem. If you’re doing your own books or using a generalist bookkeeper who doesn’t understand contractor cost structures, start here.

Vehicle and Truck Expenses

This is the single biggest deduction category for most contractors and the one that’s most commonly under-documented. Your service trucks and vans are business assets, and everything associated with them is deductible — but only if you track it.

You have two methods: actual expenses or the standard mileage rate. Actual expenses means you deduct every dollar spent on the vehicle — gas, insurance, repairs, tires, oil changes, registration, loan interest, and depreciation. Standard mileage rate (70 cents per mile for 2025; the IRS updates this annually — see the IRS standard mileage rates) is simpler but often leaves money on the table for contractors running heavy trucks with high fuel and maintenance costs. A service van averaging $600/month in gas, $200/month in maintenance, $300/month in insurance, and $400/month in depreciation is costing $1,500/month or $18,000/year in actual expenses. At 25,000 business miles per year, the standard mileage deduction would be $17,500 — close, but actual expenses usually win for contractors because truck maintenance costs are higher than what the IRS rate assumes.

The critical requirement for either method: a mileage log. Without it, the IRS can disallow the entire vehicle deduction in an audit. An app like MileIQ or the built-in tracking in most field service software handles this automatically. If your techs are driving company trucks and nobody is logging miles, you’re sitting on a deduction you can’t actually claim.

If you’re running multiple trucks, this multiplies fast. A three-truck operation with proper documentation might be looking at $45,000-$60,000 in vehicle deductions annually. Without documentation, you might claim $15,000 and hope for the best.

Tools, Equipment, and Section 179

Hand tools, power tools, diagnostic equipment, gauges, meters, recovery machines, vacuum pumps, nitrogen regulators — all of it is deductible. Small tools and supplies (anything under your capitalization threshold, usually $2,500) can be expensed immediately. Larger equipment purchases can be deducted in full the year you buy them under Section 179, up to the annual limit ($2.5 million for 2025, rising to $2,560,000 for 2026 — the cap was permanently raised under the 2025 tax law and now adjusts for inflation annually).

Where contractors miss money: they buy a $4,000 piece of equipment, pay for it out of pocket or on a personal card, and never record it in the books. Or they capitalize it and depreciate it over 5-7 years when they could have taken the full deduction in year one under Section 179. Your bookkeeper should be flagging every equipment purchase and asking: is this under the Section 179 limit? Should we expense it now or depreciate? The answer is almost always expense it now — the time value of that tax savings matters.

One more change worth knowing: 100% bonus depreciation is back, and this time it’s permanent under the 2025 tax law — the old phase-down schedule is gone. For truck and equipment purchases, that means a full first-year write-off is available even without a Section 179 election. The practical difference: Section 179 has annual caps and business income limits; bonus depreciation has neither. Your CPA now has two routes to the same answer — your job is making sure the books flag every major purchase so they can pick one.

The same applies to truck purchases and build-outs. A new service van with a custom shelving package might cost $55,000. Under Section 179, you can potentially deduct that entire amount in the year of purchase rather than depreciating it over five years. On a $55,000 purchase at a 30% effective tax rate, that’s $16,500 in tax savings this year versus spreading it over five years. Your CPA should be running this math for every major purchase.

Home Office and Workspace

A lot of HVAC, plumbing, and electrical contractors run their business from home — at least in the early years before they have a dedicated shop or office. If you have a dedicated space in your home used exclusively for business (scheduling, dispatching, admin, parts storage), you can deduct a proportional share of your mortgage or rent, utilities, insurance, and maintenance.

The simplified method gives you $5 per square foot up to 300 square feet, maxing at $1,500. The actual expense method requires calculating the percentage of your home used for business and applying that to your housing costs. For a contractor using a 200-square-foot home office and a garage bay for parts storage (say another 200 square feet), in a 2,000-square-foot home, you’re looking at 20% of housing costs. On a $2,000/month mortgage with $400 in utilities, that’s $480/month or $5,760/year in deductions — significantly more than the simplified $1,500.

Where this gets missed: contractors who use their garage for parts storage and tool staging but don’t count it as business space. If your garage is functionally a warehouse — which it is for most one-to-three-truck operations — that square footage should be included in the home office calculation.

Insurance Premiums

General liability, commercial auto, workers’ comp, tools and equipment coverage, professional liability, inland marine (covers tools and equipment in transit) — all deductible. For most contractors, insurance is a significant line item. A mid-size HVAC company might spend $40,000-$80,000 annually on insurance across all categories.

The miss here is usually workers’ comp and health insurance. If you’re paying for employee health insurance, those premiums are deductible as a business expense. If you’re self-employed and paying for your own health insurance, you can deduct 100% of premiums for yourself, your spouse, and dependents through the self-employed health insurance deduction — but this is an above-the-line deduction on your personal return, not a business expense, and it’s commonly missed because it requires your CPA to know about it. Make sure your bookkeeper is tracking these premiums separately so your CPA has the data.

Subcontractor and Labor Costs

Every dollar you pay to subcontractors (1099 labor) is a deductible business expense. This is straightforward, but documentation matters. You need a W-9 on file for every sub before you pay them, and you need to issue 1099-NEC forms for anyone you paid $600 or more during the year. Skipping the 1099s doesn’t automatically void the deduction, but it does trigger IRS penalties — currently $310 or more per form — and it invites scrutiny of those payments in an audit. File them.

For W-2 employees, wages, payroll taxes (the employer portion of FICA, FUTA, state unemployment), and benefits are all deductible. The common miss is payroll tax timing — your bookkeeper should be accruing payroll tax liability monthly, not just recording it when it’s paid quarterly. This affects both your P&L accuracy and your deduction timing.

If you’re using a mix of W-2 employees and 1099 subs (which is common in roofing and some plumbing operations), make sure the classification is correct. Misclassifying employees as 1099 contractors doesn’t just create a deduction problem — it creates an IRS audit problem with back taxes, penalties, and interest that can be devastating.

Marketing and Advertising

Google Ads, LSA (Local Services Ads), Facebook ads, vehicle wraps, yard signs, direct mail, website costs, SEO services — all deductible in the year you spend them. Most contractors get this one right because the expenses are obvious and run through a business card or checking account. But there are a few commonly missed items.

Referral fees and commissions paid to lead generators are deductible. If you’re paying Angi, Thumbtack, or any other lead platform, those costs are marketing expenses. Customer referral bonuses (paying a customer $50-$100 for a referral) are deductible too, though you may need to 1099 customers who receive more than $600 in referral payments in a year — which almost never happens for individual customers but could apply to real estate agents or property managers sending you volume.

Vehicle wraps are an interesting one. A full wrap on a service van costs $3,000-$5,000 and is sometimes capitalized and depreciated. But the IRS generally considers vehicle wraps as advertising expenses that can be deducted in full the year they’re applied. Your bookkeeper should be expensing these as advertising, not adding them to the vehicle’s asset value.

Training and Certification

EPA certifications, NATE certifications, manufacturer training, continuing education, industry conference attendance — all deductible. This includes registration fees, travel, lodging, and meals (at 50% for meals). If you’re sending techs to Carrier or Trane factory training, the entire cost — flights, hotel, per diem, and the training fee — is deductible.

Contractor licensing fees and renewals are deductible as well. State license renewals, bonding costs, and continuing education requirements to maintain your license are all legitimate business expenses that should be tracked separately, not lumped into “miscellaneous.”

Interest and Financing Costs

Interest on business loans, credit lines, equipment financing, and truck loans is deductible. If you have a line of credit you draw on for working capital during slow months, that interest is a deduction. Truck loan interest, equipment financing interest, and even credit card interest on business purchases — all deductible.

Where this gets complicated: if you used a personal loan or home equity line to fund business expenses, the interest may still be deductible as a business expense, but it requires clear documentation that the funds were used for business purposes. Your bookkeeper needs to track the flow of funds, not just the expense itself.

Commonly Missed: The Small Stuff That Adds Up

Uniforms and work clothing (including laundering costs). Cell phone bills (the business-use percentage). Software subscriptions — ServiceTitan, Housecall Pro, QuickBooks, dispatching apps, CRM tools. Bank fees and merchant processing fees (which can be 2-3% of revenue if you take a lot of credit card payments). Dues and memberships — ACCA, PHCC, local trade associations, Better Business Bureau. Bad debt — if a customer doesn’t pay and you’ve exhausted collection efforts, you can write off the receivable.

None of these are individually transformative, but across all of them, a typical contractor is looking at $5,000-$15,000 in annual deductions that either aren’t tracked or are miscategorized. At a 30% effective tax rate, that’s $1,500-$4,500 in tax savings from just getting the small stuff right.

What Your Bookkeeper Should Be Doing Monthly

If your bookkeeper is doing their job right, tax season should be boring. Every expense is already categorized correctly. Vehicle mileage is logged. Equipment purchases are flagged for Section 179 treatment. Subcontractor W-9s are on file. Insurance premiums are tracked separately by type. There’s nothing to scramble for in January because it was all captured in real time.

Here’s the monthly checklist your bookkeeper should be running: reconcile all bank and credit card accounts. Verify vehicle mileage logs are current. Review any equipment purchases over $500 for proper categorization. Confirm subcontractor payments have W-9s on file. Track insurance premium payments by category. Review any personal expenses that ran through business accounts (and flag them for removal). Document any home office or workspace changes.

If your bookkeeper isn’t doing this — or if you’re doing your own books and this list sounds exhausting — that’s a sign you’ve outgrown DIY bookkeeping. The cost of a professional bookkeeper (a generalist might run $500-$1,500/month; specialized contractor bookkeeping with job costing typically runs more) is almost always recovered in tax savings from better deduction tracking alone, before you even count the time savings and financial clarity.

The Bigger Picture: Clean Books Save Money Every Year

The contractors who consistently pay the least in taxes aren’t gaming the system. They just have clean books. Every deductible expense is documented, categorized, and ready for their CPA. They’re not leaving $10,000-$30,000 in legitimate deductions on the table because nobody was paying attention to the bookkeeping.

If you’re running a home services company and your books aren’t giving you this level of clarity, that’s what we help with. We restructure contractor chart of accounts, clean up categorization, and build the monthly close process that makes tax season a non-event. If you want to talk through what your books should look like, reach out.

Related: Chart of Accounts for Home Services Contractors

Related: What Your Bookkeeper Should Tell You Every Month

About the Author

Raymond Gong

Raymond Gong is one of the senior partners of Profitability Partners, a fractional CFO and accounting firm built exclusively for home services companies — HVAC, plumbing, electrical, and roofing operators doing $5M–$30M in revenue. Prior to Profitability Partners, Raymond was a private equity professional at Black Diamond Capital Management and Third Lake Partners, a large family investment office. Raymond runs the books, the reporting, the profitability optimization, and the exit prep for contractors nationwide, working daily inside ServiceTitan, Housecall Pro, and QuickBooks — turning messy operational data into financials owners can actually run the business on, and that buyers and lenders take seriously. Raymond is a graduate of Vanderbilt University and is based in Tampa, FL.

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Raymond Gong

Raymond Gong is one of the senior partners of Profitability Partners, a fractional CFO and accounting firm built exclusively for home services companies — HVAC, plumbing, electrical, and roofing operators doing $5M–$30M in revenue. Prior to Profitability Partners, Raymond was a private equity professional at Black Diamond Capital Management and Third Lake Partners, a large family investment office. Raymond runs the books, the reporting, the profitability optimization, and the exit prep for contractors nationwide, working daily inside ServiceTitan, Housecall Pro, and QuickBooks — turning messy operational data into financials owners can actually run the business on, and that buyers and lenders take seriously. Raymond is a graduate of Vanderbilt University and is based in Tampa, FL.