Built around B&O, sales tax on labor and hour-based L&I premiums
Washington has no income tax, so contractors assume the tax side is simple. Then the B&O bill arrives on gross receipts you have already spent, the Department of Revenue asks why custom construction and a spec house were reported the same way, and retainage on a public job sits unreleased because DOR, ESD and L&I have not signed off. Construction accounting in Washington has to start there: B&O classification, sales tax charged at the job site rate, and labor burden built from L&I hours rather than a percentage of payroll, because industrial insurance here is priced by the hour.
On the ground
Seattle, Washington
This is where Washington contractors lose money quietly. The B&O classification, whether sales tax applies to the whole contract or only to your material purchases, and which local city tax you owe all depend on how the contract is written and where the work happens. Our construction tax planning starts by reading your contracts, not your ledger.
Every construction platform claims to have a "QuickBooks integration." Most break the moment your books need to be accurate. Sales tax mismaps, retainage disappears, change orders create duplicates, and job costing reports stop matching project reality. We fix the integration so your software, your books, and your job‑level numbers all tell the same story.
Also work with Foundation, Sage 100, Bill.com, ADP, Gusto, Ramp, and more. See all platforms we integrate →
Industrial insurance in Washington is priced per hour worked in a risk class, not as a percentage of wages. Any burden rate applied as a flat percentage of payroll is therefore wrong on every job, in one direction or the other. We rebuild burden from hours and classes so the labor number on your cost report is the number you actually paid.
State and local public works in Washington run on intents, affidavits and certified payroll filed with Labor and Industries. All three come out of payroll, and all three have to agree with the labor cost sitting in your job report. We run them from one process so an audit finds them saying the same thing, and so closeout is not held hostage by a missing subcontractor affidavit.
Washington contracts hold retainage on public work and often on private work too, and that money is the difference between a profitable year and a working capital problem. We produce a monthly work in progress schedule on percentage of completion and keep retainage receivable and payable as their own tracked balances with the conditions that release them.
Because B&O is charged on revenue rather than profit, growth in Washington costs cash before it produces any. Add retainage, a wet winter and a bonding line that has to be justified, and the decision to take a bigger job is a financial one first. Our controller services and CFO services answer what you can carry.
They didn’t just record transactions and call it a day. They built a custom chart of accounts around how a remodeling company actually runs, did a full catch-up on years of bookkeeping inside QuickBooks Online, and now stay on top of my monthly bookkeeping and payroll. Every step, they broke it down in simple terms instead of burying me in accountant talk.
FinTruction rebuilt the whole thing from the ground up, with real job costing, work in progress, and retainage. They didn’t just hand me reports and disappear; they walked me through my numbers until I understood them.
Sahil and his team handle the bookkeeping and job costing for my painting business. They cleaned up my books and set up integrations that give me accurate, timely job costing with solid weekly data. Reliable, detailed, and genuinely invested in getting the numbers right.
FinTruction is the only bookkeeping team we’ve found that truly understands construction accounting and WIP reporting. They aligned our income and costs across 21 jobs and gave us full, monthly transparency. Fast, accurate, and an indispensable partner.
When I came to FinTruction I had no financial structure. No job costing, no WIP tracking, books behind. They did a full cleanup and rebuilt job costing and WIP tracking in QuickBooks. Now I know what’s billed, what’s owed, and where every job stands.
A couple of minutes from a contractor we support, sharing what working with FinTruction has been like and what changed once their numbers finally made sense.
Washington taxes contractors in a way almost no other state does, and the rules turn on how the contract is structured rather than on what you built. A generalist bookkeeper has no reason to know that, which is why the errors are so consistent.
Washington is not one construction market, it is two with a mountain range between them. The Puget Sound corridor from Everett through Seattle and Bellevue down to Tacoma and Olympia runs on tech campus and tenant improvement work, high-rise and mass timber residential, Sound Transit light rail extensions, the Northwest Seaport Alliance terminals in Seattle and Tacoma, Boeing facilities in Everett and Renton, and military construction at Joint Base Lewis-McChord. Labor here is expensive, often union, and the sites are constrained enough that schedule risk shows up in the cost report before anyone admits it out loud. Most of that work is administered in Procore, so we connect Procore to QuickBooks and let commitments and change orders reach job cost without a second round of data entry.
East of the Cascades the economics change completely. Spokane has healthcare, university and downtown redevelopment work. The Columbia Basin around Quincy and Moses Lake has drawn heavy data center construction, helped along by cheap hydropower and a state sales tax exemption aimed at eligible data center equipment. The Tri-Cities carry Hanford-related federal work, which brings Davis-Bacon and federal government contracting rules with it. Yakima and the Walla Walla valley build food processing, cold storage and agricultural facilities. Labor rates, open shop prevalence and overhead are all different from Seattle, and a contractor bidding both sides on one blended rate is guessing.
What both halves share is the state tax regime, and that is the part that catches people. There is no personal or corporate income tax here, which reads like good news until the first B&O return. B&O is charged on gross receipts with no deduction for what the job cost you, so a thin-margin project and a strong one carry the same tax on the same revenue. On top of that, whether you collect retail sales tax on your labor depends on the type of construction, and the rate depends on where the site is rather than where you are. Then dozens of cities layer their own B&O tax and their own apportionment rules on top.
Add the weather. West of the mountains the winter is wet rather than frozen, which slows sitework and exterior trades without stopping them, and east of the mountains it freezes and then bakes, with wildfire smoke costing outdoor days in late summer. Production peaks in the middle of the year while retainage and slow closeouts push the cash into the following one. That gap is where Washington contractors get into trouble, and it is measurable months in advance if the books are actually telling you something. Our guide to improving construction cash flow walks through the mechanics, and a construction accountant who tracks retainage and B&O separately can see the squeeze coming while there is still time to act on it.
A general bookkeeper can record transactions. Construction accounting is a different job.
| What you need | Generic local bookkeeper | FinTruction |
|---|---|---|
| Job-level costing | Lumps all jobs into one P&L | Cost codes and margin per project |
| WIP & revenue recognition | Cash-basis, no WIP schedule | Monthly WIP with over/underbilling |
| Retainage tracking | Buried in AR/AP, often missed | Tracked receivable & payable by contract |
| Bonding & lender packages | Not equipped to produce them | Bonding-ready statements and backlog |
| Construction software | QuickBooks set up like a retail shop | QuickBooks + integrations tuned for contractors |
We support contractors on both sides of the Cascades, from mechanical and electrical crews on Puget Sound tech and transit projects to site work and agricultural facility builders in the Columbia Basin.
Running a Construction Company in Washington?
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Business and Occupation Tax and Contractor Classifications: Washington replaces an income tax with a gross receipts tax administered by the Department of Revenue, and construction does not sit in a single classification. Custom construction for a landowner, speculative building on your own land, public road construction for a state or local body, and federal government contracting are each treated differently, with different rates and different treatment of the materials you buy. Reporting all revenue under one classification because that is how the file was set up years ago is the most common and most expensive error we find in Washington books.
Retail Sales and Use Tax on Construction Contracts: On custom construction the contractor is making a retail sale, so sales tax applies to the entire contract price including labor, which surprises anyone used to a labor exemption elsewhere. A speculative builder is instead the consumer and pays tax on materials and subcontracts. Washington sources the sale to where the work is performed, so the correct rate follows the job site across dozens of local taxing districts. Materials bought without tax, including anything picked up across the Oregon line, generally create a Washington use tax liability when they are consumed here.
Contractor Registration and Bonding with Labor and Industries: Washington does not run a trade examination for general contractors the way many states do. Instead you register with Labor and Industries as a general or specialty contractor, carry a surety bond and general liability coverage at statutory minimums that have been increased in recent years, and maintain industrial insurance. Electricians and plumbers are separately licensed. You are also expected to verify that your subcontractors are registered. Bond premiums, registration and insurance are overhead costs that belong in your burden and your bid, not in a miscellaneous expense account.
Industrial Insurance Priced by the Hour: Washington is one of the few monopolistic workers compensation states. Unless you are certified as self-insured, coverage comes from the Labor and Industries state fund and the premium is assessed per hour worked in each risk classification, with a portion deducted from the worker. Hours have to be reported accurately by class, and burden calculated as a flat percentage of gross wages will never match. The state also collects Paid Family and Medical Leave and WA Cares premiums through payroll, which belong in the same burden calculation.
Prevailing Wage under RCW 39.12: Public works in Washington require payment of prevailing wage rates set by Labor and Industries for the trade and county, a Statement of Intent to Pay Prevailing Wages approved before you are paid, certified payroll records, and an Affidavit of Wages Paid before final payment and retainage release. Larger state projects carry apprenticeship utilization requirements. Every one of those obligations is produced from payroll data, which is why we treat prevailing wage as an accounting function rather than as paperwork for the office to catch up on.
Retainage on Public Works under RCW 60.28: Public bodies in Washington may retain up to five percent of the contract, and a contractor can generally elect how it is held, including posting a bond in lieu of retainage. The part contractors underestimate is the release. Before retained funds are paid out, the agency has to obtain releases from the Department of Revenue, the Employment Security Department and Labor and Industries. Your own filing status therefore controls your own cash, and a late excise return can hold up money on a job that finished cleanly months ago.
Lien Rights and Multi-State Exposure: Washington lien law under RCW 60.04 sets a short window to record a claim after you last furnish labor or materials, roughly ninety days, followed by a limited period to foreclose, and parties without a direct contract with the owner face an earlier notice requirement. We are not attorneys and we do not file notices. We keep unpaid amounts organized by job, tier and date furnished so the deadlines run off real data. The same discipline covers border work, where crews in Vancouver or Spokane pick up Oregon and Idaho income tax and withholding obligations that Washington itself never asks about.
A fair question if you already have a bookkeeper, a payroll service and a CPA who does the return. Here is the honest answer.
Most contractors here do not need new software. They need what they already pay for set up for construction and connected to the accounting, with the Washington-specific parts built in rather than patched on at filing time.
Most QuickBooks files we inherit were configured for a business that sells products off a shelf. For a contractor in this state that means no cost codes, retainage hiding inside receivables, one sales tax rate applied to everything, and no way to tell custom construction revenue from speculative building revenue when the B&O return is due.
Is your QuickBooks file working against you?
If your project managers already track budgets, commitments and change orders in a construction platform, the office should not be retyping any of it. We connect the field system to the accounting so the numbers agree and the month does not open with an argument about whose figure is correct.
One set of numbers that the field and the office both believe.
Once the systems are connected, reporting stops being a history lesson. These are the reports Washington contractors use to decide what to chase and what to walk away from:
See how we have done this for other contractors in our construction accounting case studies.
The Washington Business and Occupation tax is a gross receipts tax administered by the Department of Revenue, charged on revenue with no deduction for labor, materials or subcontractors, so a thin-margin job carries the same tax as a profitable one. The rate depends on which classification the work falls under, and construction has several. Custom construction for a customer who owns the land, speculative building on land you own, public road construction for a state or local body, and federal government contracting are each reported differently. Most contractors report everything in one classification because nobody told them there was more than one, and that is either a steady overpayment or an assessment waiting to happen.
Yes, on custom construction. Washington treats a contractor who builds, repairs or improves real property for a customer who owns that property as making a retail sale, so retail sales tax applies to the entire contract price including labor, not just the materials. Contractors arriving from states where labor is exempt get this wrong constantly. Speculative building reverses it: if you build on land you own in order to sell, you are the consumer, you pay tax on materials and subcontracts, and the eventual sale is a real estate transaction. Public road construction for a municipality follows a third rule. The difference is the whole tax on the job, not a rounding error.
Washington gates public works retainage on your tax and premium filings, not only on the work. Under RCW 60.28 the awarding agency must obtain releases from the Department of Revenue, the Employment Security Department and Labor and Industries before it can pay out retained funds. If your excise tax returns, unemployment reports or industrial insurance premiums are behind, the money stays held even though the job closed out cleanly. Contractors regularly chase a general contractor for months over cash that their own filing backlog is holding up. Keeping the filings current is a cash flow function in this state, not an administrative one.
Washington is a monopolistic workers compensation state, so unless you are certified as self-insured your industrial insurance comes from the Labor and Industries state fund, and the premium is assessed per hour worked in each risk classification rather than as a percentage of payroll. Part of it is deducted from the worker. That breaks the burden math almost every payroll setup uses, because a flat percentage of gross wages overstates the cost of a high-rate journeyman and understates the cost of a lower-paid crew working long hours. Job costing in Washington has to build burden from hours by risk class to be accurate.
Yes. Washington public works governed by RCW 39.12 require a Statement of Intent to Pay Prevailing Wages filed with Labor and Industries and approved before you can be paid, certified payroll records covering the work, and an Affidavit of Wages Paid filed and approved before final payment and retainage release. Both forms carry a filing fee and both are required from your subcontractors as well. Larger state projects add apprenticeship utilization targets. The recurring failure is a missing subcontractor affidavit holding up an entire closeout, which is a records problem long before it becomes a compliance one.
Yes, in most cases. Dozens of Washington cities levy their own local B&O tax on top of the state tax, and Seattle, Tacoma, Bellevue and Everett are among them, each with its own registration, thresholds and rules for apportioning gross receipts to that city. Sales tax adds a second layer, because Washington sources construction to where the work is performed, so the correct rate follows the job site rather than your office address. A contractor with a Kent yard billing work in three cities is usually under-collecting in some and over-collecting in others. Coding the site location onto the job is what fixes it.
Crossing the Oregon or Idaho line creates genuine multi-state exposure. A Vancouver contractor working in Portland picks up Oregon income tax filings, Portland-area local taxes and payroll withholding for hours worked across the river. A Spokane contractor working around Coeur d Alene picks up Idaho income tax and withholding. There is a trap running the other way too: buying materials in Oregon without paying sales tax and then consuming them on a Washington job creates a Washington use tax liability that almost nobody accrues. Splitting payroll by work state and accruing use tax as it arises keeps that out of an audit.
The cost base and the project mix are genuinely different. Puget Sound work is dominated by tech campuses, data centers, high-rise and mass timber residential, Sound Transit light rail and port and marine work, much of it union, on constrained sites with long approval cycles. East of the Cascades you get agricultural and food processing facilities, warehousing, healthcare and university expansion, Hanford-related federal work near the Tri-Cities and large data center construction in the Columbia Basin, much of it open shop at a very different labor rate. One blended overhead and burden rate does not survive that spread, so a contractor bidding both sides needs the two cost structures visible separately.
FinTruction serves contractors across all of Washington State. That includes the Puget Sound corridor from Everett through Seattle, Bellevue, Redmond, Kirkland, Kent and Renton down to Tacoma and Olympia, Southwest Washington around Vancouver and Longview, Eastern Washington including Spokane, the Tri-Cities, Yakima and Wenatchee, and the Peninsula, Bellingham and the northern counties. Our work is fully remote, so a contractor in Walla Walla gets the same construction accounting and construction bookkeeping as one working downtown Seattle, without paying toward an office nobody visits.
Pricing is a flat monthly fee based on transaction volume, active jobs and reporting needs, so asking a question does not start a clock. Start with the free Audit: send your current accounting file and your most recent job profitability or WIP report and we will tell you what is broken, what it is costing you and what it would take to fix. On Washington files we look at B&O classification and sales tax treatment first, because that is where contractors here leak the most money without knowing. Sahil Ahmad, CPA reviews the work, so a construction CPA has actually read your file.
FinTruction provides construction accounting and construction bookkeeping across Washington State. Select your city below for job costing, WIP reporting and contractor accounting support in your market.
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