How to Stop Paying Sales Tax You Don’t Owe: Ways Subcontractors Can Protect Their Profitability

Too many subcontractors are paying unnecessary sales tax on materials—specifically when working on tax-exempt projects. The issue, while unintentional, is the result of a lack of clarity between subcontractors, suppliers, and general contractors about what qualifies as exempt.

Sales tax might not be an area of focus for your business when your top priorities are winning projects and managing crews, but it can quietly cost your business tens of thousands of dollars a year or more if you’re not paying attention.

At Billd, we work with commercial subcontractors every day and understand how easily this can get overlooked. That’s why we wanted to provide a guide to help you avoid unnecessarily paying too much for materials. Here’s what you need to know about how sales tax exemptions work and what role they play as part of a financial strategy.

Why Sales Tax Matters in Construction

In most states, sales tax applies to tangible personal property like the materials you buy. But when those materials are incorporated into a building or public works project, the rules can change.

The catch: whether you owe sales tax is determined by state law and often depends on who the customer is and what the project is for, not just where the materials are purchased.

The good news is if you’re working on a qualified tax-exempt project, you can often avoid some or all of the associated sales tax. The bad news is if you don’t catch it early and your supplier charges you sales tax, getting it back can be a hassle.

Common Tax-Exempt Projects

Every state has its own rules, but in general, the following are examples of tax-exempt projects:

1. Government-funded projects, which include:
   • City, county, state, or federal government buildings
   • Schools, police stations, fire stations, libraries
   • Military facilities and public infrastructure
2. Non-profit and religious institutions, including:
   • Churches, temples, and other houses of worship
   • Non-profit hospitals or educational institutions
3. Public works and infrastructure, such as:
   • Road, bridge, and highway projects
   • Municipal utilities and water treatment plants
4. Other exempt entities can include:
   • Some housing authorities, universities, and charitable organizations

If your project falls into one of these categories, your material purchases may be exempt, but it’s your responsibility to make sure that exemption is properly documented.

How the Tax Exemption on Materials Actually Works

Here’s where subcontractors often get tripped up: While the project owner or GC might be the tax-exempt entity, you as the subcontractor are the one buying the materials. To qualify for the sales tax exemption, you need to have a valid sales tax exemption certificate or resale certificate on file with your suppliers.

Without that documentation, the supplier will automatically charge sales tax. Once it’s charged and paid, recovering it can be time-consuming and difficult.

To prevent paying taxes on tax-exempt materials, before you order materials:

1. Confirm whether the project is tax-exempt.
2. Get a copy of the owner’s or GC’s exemption certificate. This may be included in the project contract, but if not, request it from the GC.
3. Provide your supplier with a properly completed resale or exemption certificate referencing that project.

If you’re using construction-specific financing (like Billd’s Material Financing), let your finance partner know and make sure the financing aligns with that exemption.

What’s Typically Exempt vs. Taxable

Here’s a general breakdown of what is considered tax-exempt. However, be sure to check your state’s specific rules:

Usually sales-tax exempt (if the project qualifies):

• Materials permanently incorporated into the structure (steel, concrete, drywall, wiring, etc.)
• Building systems and fixtures (HVAC, plumbing, electrical)
• Equipment rented or purchased specifically for the exempt project (sometimes)

Usually taxable:

• Tools and consumables (drill bits, gloves, blades, fuel, etc.)
• Temporary equipment like scaffolding, formwork, or portable lighting
• Administrative purchases not tied to a specific job

One of the key questions to ask when considering a material’s exemption status: Is this material becoming a permanent part of a tax-exempt project?

If yes, the materials may be exempt.

How to Spot a Supplier Charging You Incorrectly

Suppliers don’t always know which of your projects are tax-exempt. They see hundreds of transactions every month, so it’s recommended you notify them upfront before completing your purchase.

Check every invoice and purchase order for a sales tax line item. If you see it listed and the project should be exempt:

• Contact your supplier immediately
• Provide the exemption certificate tied to the project
• Request a revised, tax-exempt invoice

Why This Matters

Even small oversights add up. A 8.25% tax on $200,000 of materials is $16,500—money that should stay in your pocket. Compound that with purchases across multiple projects throughout the year and you can see why it makes financial sense to stay diligent.

Missing sales tax exemptions can:

• Inflate your material costs unnecessarily.
• Hurt your cash flow and profitability.
• Undermine your bids if your competitors are managing it correctly.

Beyond the dollars, this comes down to running a professional, financially disciplined business. Getting it right helps you price more competitively, manage margins, and avoid tax headaches during audits.

How Billd Helps

When our team recognizes that a project is tax-exempt, we’ll try to work directly with you and your supplier to ensure they have the proper documentation so you don’t get stuck paying taxes you don’t owe.

We see this as part of our mission: helping subcontractors make financially smart, informed decisions that protect their bottom line and empower them to do the best work of their lives.

Bottom Line

Sales tax might seem like a small detail, but for subcontractors managing multiple six- or seven-figure projects, it can mean the difference between hitting your margin targets or missing them.

The best way to keep these dollars in your business is to:

• Know when projects are tax-exempt
• Keep your certificates organized
• Double-check every supplier invoice

Smart subcontractors don’t just build great projects—they protect their business from unnecessary costs. And Billd is here to help them do it. For more information on financial best practices, visit the resources available in the Billder’s Boardroom.

Disclaimer: The information in this article is not intended as legal or financial advice. You should always seek the advice of independent professionals before making decisions that impact your business.