Running a construction or contracting business in Washington State is one of the most financially complex things a person can do. Revenue looks healthy, projects wrap up, invoices go out — and yet at the end of the year, many contractors find themselves wondering where the money went, or facing a tax bill they did not see coming.
In our work with contractors across Pierce County and the South Puget Sound region, we have traced a large share of these problems back to one root cause: inadequate construction job costing. It is not glamorous, but it is the most important financial discipline a contractor can build. Get it right and you know exactly where you make money, where you lose it, and how to defend every dollar at tax time.
What Is Construction Job Costing?
Construction job costing is the practice of tracking every dollar of cost — labor, materials, subcontractor payments, equipment use, and job-specific overhead — back to a specific project. The goal is to know the actual profit or loss on each job, not just a company-wide average at year end.
Most contractors have a general sense of whether a project went well. Job costing makes that sense precise. When done correctly, you can answer questions like: Did we actually make money on that commercial build in Puyallup? Why did the remodel come in over budget when the estimate looked solid? These are not just operational questions — they are tax questions, too.
Why Construction Job Costing Matters for Your Taxes
Direct Job Costs Are Fully Deductible
The IRS allows contractors to deduct the direct costs associated with each project, provided those costs are properly documented and allocated to the job. Deductible direct costs include:
- Direct materials — lumber, concrete, fixtures, and all materials consumed on the job
- Direct labor — wages and payroll taxes for workers tied to that specific project
- Subcontractor payments — amounts paid to licensed subs performing work on the contract
- Equipment costs — fuel, depreciation, and rental costs for equipment used on a specific job
- Job-specific overhead — permits, bonding, and insurance allocated directly to the project
When costs are tracked at the job level, claiming them is straightforward. When they are not, contractors routinely over- or under-report income, miss deductions they are entitled to, and find themselves unable to defend their numbers if the IRS comes looking.
The Audit Risk of Poor Records
An audit of a construction company without clean job cost records is a painful experience. The IRS expects job-level documentation — a properly maintained job cost ledger tying each expense to a specific project, with receipts and time records to match. We have helped contractors in Western Washington reconstruct records under pressure. It is expensive and stressful. Building the system before you need it is the easier path.
The Main Job Cost Categories Every Contractor Should Track
Good construction accounting separates costs into four main categories. Direct materials covers everything that physically goes into the project, allocated to the job at time of purchase or use — not lumped into a general supplies account.
Direct labor means wages paid to field employees on the job, plus payroll taxes and workers' compensation premiums. Time tracking by project is essential — without it, labor costs become estimates, and estimates create tax risk.
Subcontractor costs should be allocated to the specific job each sub performed on. These amounts also determine your 1099-NEC obligations at year end.
Equipment costs — for owned equipment: depreciation, maintenance, and fuel. For rented equipment: the rental invoice. Either way, the cost belongs on the job that used it, not in a general overhead pool.
The Overhead Allocation Problem
One of the most common mistakes in construction company accounting is mixing general overhead into job costs incorrectly. General overhead — office rent, administrative salaries, software — supports the business as a whole, not any single project. When it is dumped into individual job cost reports without a rational allocation method, profitability reports become unreliable. You may think a job is unprofitable when your pricing is actually fine, or you may underbid future work because your cost history is distorted.
Getting this right requires a clear separation between direct job costs and indirect overhead, with a consistent allocation method applied across every project.
Percentage-of-Completion Accounting and Washington State Contractors
Many contractors in Washington State working on long-term contracts — projects spanning more than one tax year — are required to use the percentage-of-completion method for tax reporting. Under this method, you recognize income and expenses in proportion to how much of the project is complete at year end, rather than waiting until the contract closes.
This is a detail many contractors across the South Puget Sound region do not realize applies to them, and it has a direct impact on when taxes are owed. Accurate percentage-of-completion reporting requires accurate job cost data. If your costs are wrong, your income recognition is wrong — and your tax bill follows.
Equipment Depreciation: Section 179 and Bonus Depreciation
Construction companies often carry significant equipment — excavators, trucks, trailers, lifts, compressors. The tax code offers meaningful deductions for these assets. Section 179 allows you to deduct the full cost of qualifying equipment in the year it is placed in service, up to an annual limit currently over $1 million for most businesses. Instead of depreciating a $120,000 excavator over five years, you may be able to deduct it entirely in year one.
Bonus depreciation provides an additional first-year deduction for qualifying property, though the phase-out schedule has shifted in recent years and requires careful planning. Job costing ties directly into both: knowing which jobs a piece of equipment supported documents its business use, a requirement for claiming depreciation. Without job records, you are relying on memory to defend a potentially large deduction.
A Word on Contractor vs. Employee Classification
If your business uses subcontractors, the IRS and Washington State Department of Labor and Industries both care about whether those workers are properly classified. Misclassifying employees as independent contractors creates exposure — unpaid payroll taxes, penalties, and potential back wages under state law. If your field staffing situation is complex, reviewing classification with a knowledgeable advisor is worth the time.
How Green Consulting Helps Construction Businesses Get This Right
We are a licensed accounting and financial consulting firm based in Puyallup, and construction company accounting is one of our core specialties. We work with general contractors, subcontractors, and specialty trades across Pierce County and Western Washington — helping them set up job costing systems that actually get used, review cost allocation methods, plan equipment depreciation, and apply the percentage-of-completion method correctly.
If you are running a contracting business in Washington State and are not confident your job costing is giving you accurate, defensible numbers, that is worth a conversation.
Frequently Asked Questions
What is the difference between job costing and regular bookkeeping?
Regular bookkeeping tracks income and expenses at the company level. Job costing goes deeper — every dollar is tracked back to the specific project it belongs to. You can be profitable overall while losing money on specific project types, and without job costing, you would never know which ones. Job-level records also provide the documentation needed to substantiate deductions if you are audited.
Which contractors are required to use the percentage-of-completion method?
Generally, contractors with average annual gross receipts over $30 million must use it for long-term contracts, though smaller contractors may qualify for an exception. Washington State contractors working on multi-year commercial or public projects should review their situation with a tax advisor — getting it wrong means recognizing income in the wrong year, and the tax bill follows.
Can I deduct subcontractor payments even if I did not file 1099s?
The deduction is generally still available, but failing to file required 1099-NEC forms for subcontractors paid $600 or more creates IRS penalties and draws scrutiny to your records more broadly. Build subcontractor tracking and 1099 compliance into your annual workflow rather than treating it as an afterthought.
How does Section 179 interact with job costing for equipment purchases?
Section 179 lets you deduct the full purchase price of qualifying equipment in the year it is placed in service. To support that deduction, you need to document the equipment's business use — which jobs it was used on and what percentage of its total use was business-related. Job costing records that capture equipment costs by project create a natural audit trail for this.
My construction business is in Puyallup and I handle my own bookkeeping. When should I bring in a professional?
Earlier than most owners expect. The common triggers are running multiple simultaneous projects, bringing on subcontractors, acquiring significant equipment, or taking on a contract that spans more than one tax year. Any one of these adds complexity that basic bookkeeping and end-of-year tax prep are not designed to handle. A professional who understands construction accounting specifically can put systems in place that save you money and protect you from risk.
