Deductions in a field service company start with the books kept all year
Updated 16 October 2026
Field service companies often miss deductions because an expense was never recorded in the right category during the year. The deduction existed. The record did not. This page lists the expense categories that plumbing, heating and cooling, electrical, landscaping and other trade companies track, and the records behind each one. A CPA decides how each category applies to the company's entity type, income and state.
The main categories
| Category | What it covers |
|---|---|
| Work vehicles | Trucks and vans used in the business, claimed by mileage or by actual expenses such as fuel, maintenance, insurance and depreciation, based on business use. |
| Tools and equipment | Hand tools, power tools and machinery, either expensed or depreciated, which can include Section 179 or bonus depreciation. |
| Materials and supplies | Parts, consumables and job materials used in the work. |
| Labor and subcontractors | Wages, payroll taxes, benefits and payments to subcontractors reported on a 1099. |
| Home office | Space in the home used regularly and only for the business, by the simplified method or the actual-expense method. |
| Insurance | General liability, commercial vehicle, workers' compensation and bonding. |
Each category needs its own account in the chart of accounts. An expense coded to the wrong account, or left in an owner's personal card, reaches a CPA as the wrong figure or as no figure at all.
An owner's truck covers 24,000 miles in a year. The mileage log shows 21,600 of those miles on business trips, so business use is 90%. The bookkeeper records fuel, repairs and insurance for the truck in their own accounts through the year. At year end a CPA has both the 90% figure and the actual costs, and chooses the method that applies. The figures are an illustration.
Trucks and equipment: the timing choice
When a company buys a truck, a major piece of equipment or a fleet upgrade, the deduction does not always have to be spread across many years. Section 179 and bonus depreciation can allow a large share of the cost, and sometimes all of it, to be deducted in the year the asset goes into service. Taking more of the deduction now leaves less to deduct in later years. The choice turns on this year's income against next year's, and a CPA advises on it as part of the year's tax planning.
A plumbing company buys a new service truck in November and puts it on the road on 20 November. The books record the purchase price, the loan, the trade-in and the in-service date, with the invoice attached. In December a CPA reviews the year's income with the owner and decides how much of the truck to deduct this year. Every figure the CPA needs is already in the books. The figures are an illustration.
Categories that are often left uncoded
- Continuing education and licensing: trade licenses, certifications, renewals and training.
- Software and dispatch tools: field service platforms, scheduling, accounting and payment apps.
- Uniforms and safety gear: branded uniforms, boots, gloves and protective equipment.
- Bank and merchant fees: card processing fees and business banking charges.
- Retirement contributions: plans such as a SEP-IRA or a solo 401(k) for owners.
- The qualified business income deduction, which many pass-through trade companies can claim.
- Phone and internet: the business share of mobile and internet costs.
Most of these are small, frequent charges that land on a card or come out of a deposit. They go missing when they are never given an account of their own.
Precision Garage Door Service's average business completes about 4,730 jobs a year, roughly 91 a week. When card payments arrive in the bank net of the processor's fee, each Precision Garage Door deposit is smaller than the jobs it pays for. A bookkeeper who records the deposit at the net figure leaves every fee off the expense lines. Recording the gross sale and the fee separately puts the full year of merchant fees in front of a CPA.
Records that support each deduction
Each deduction depends on the record behind it. Companies that pay more than they need to usually have the expense and lack the record: a mileage log that was never kept, an equipment purchase coded to repairs, a receipt that was thrown away. Books that are categorized through the year record every deductible cost and the evidence for it, so each deduction can be supported if the tax authority asks. The owner arrives at tax season with the figures already in place.
An electrical contractor pays 6 subcontractors during the year. The bookkeeper sets each one up as a named vendor before the first payment and codes every payment to that vendor in a subcontractor account. At year end the books show the total paid to each of the 6, and a CPA uses those totals for the 1099 forms and the deduction. The figures are an illustration.
What this means for an owner
Vehicles, tools and equipment, materials, labor and subcontractors, home office and insurance are the main categories. Licenses, software, uniforms, merchant fees, retirement contributions, the qualified business income deduction and phone costs are the ones most often left uncoded. Section 179 and bonus depreciation change when a purchase is deducted, and a CPA advises on the timing. Each category needs its own account and its own records through the year. A CPA applies the rules to the company.
Books kept in these categories
Averan keeps the books in the categories above, attaches the records to each transaction and closes every month and the year. The bookkeeping service page lists what each month includes. Averan also provides controller and fractional CFO work as the company grows.
Where to next
Want the books off your plate?
Book a short call, and we'll give you an expert view of your situation.
Free Consult →If you want this done for you
What happens next
Reading about it and having it done are different things. Here is exactly what happens if you want the second one.
- The call takes thirty minutesYou describe the business and where the numbers are letting you down. We give you an expert view of your situation, and what we would start with. There is no pitch deck.
- We look at the fileYou give us read access to the books as they are. We come back with what is wrong, what it will take to fix, and whether the answer is bookkeeping, controller work, or something else.
- We send a written scope and a priceIt lists what we do each month, what you get, the date it lands and the fee. We agree it before anything starts, and it does not change unless you agree.
- We take over the books and close the first monthWe set up access and systems and enter the opening balances. The first close lands on the date in the scope, and every one after it does too.