Contractors and home improvement businesses in New York face some of the most complex sales tax rules in any industry — and the New York State Department of Taxation and Finance knows it. Construction and contracting are consistently among the highest-audited sectors in the state, and the assessments that come out of these audits are frequently substantial.
The complexity is not accidental. New York's sales tax treatment of contractor work depends on the type of contract, the nature of the work, who the customer is, and, in some cases, what specific materials are used. Getting it right requires a level of knowledge that most contractors — and many accountants — simply do not have.
While our office is based on Long Island, we represent contractors and home improvement businesses facing NYS sales tax problems throughout New York State, including Nassau County, Suffolk County, Queens, and across the five boroughs.
The fundamental rule: capital improvements vs. repair, maintenance, and installation
The most important distinction in New York contractor sales tax is between capital improvement work and repair, maintenance, and installation work. The tax treatment of these two categories is completely different.
A capital improvement is work that adds value to real property, prolongs its useful life, or adapts it to a new or different use. When a contractor performs a capital improvement, the contractor pays sales tax on the materials purchased for the job, but does not charge sales tax to the customer on the contract price. The customer's payment for a capital improvement contract is not subject to sales tax.
Repair, maintenance, and installation work — often called RMI work — is taxed differently. When a contractor performs repair, maintenance, or installation services, the entire charge to the customer — both labor and materials — is subject to New York sales tax.
This distinction sounds straightforward, but it creates enormous complexity in practice. Whether a specific job qualifies as a capital improvement or RMI work is not always obvious, and contractors who mis-classify their work — even inadvertently — can face significant audit assessments.
Common misclassifications that trigger contractor audits
DTF auditors who examine contractor businesses look carefully at how jobs are classified. Several patterns commonly emerge in contractor audits:
Treating all work as capital improvements. Some contractors take the position that virtually all of their work is capital improvement work and therefore charge no sales tax on any jobs. Auditors will examine contracts, invoices, and project descriptions carefully and re-classify work they believe should have been taxed as RMI.
Failing to charge sales tax on service calls and minor repairs. Small repair and maintenance jobs — HVAC service calls, minor plumbing repairs, routine maintenance work — are clearly taxable, but some contractors do not charge sales tax on these jobs. Auditors will add up the untaxed service revenue and assess tax on the full amount.
Incorrect handling of materials on RMI jobs. On RMI work, the entire charge, including materials, is taxable to the customer. Some contractors purchase materials without paying tax under a resale exemption, but then fail to collect tax from the customer on the materials component of the job. This creates a liability either way — tax should have been paid either at purchase or at billing.
Subcontractor issues. When a general contractor uses subcontractors, the sales tax treatment of payments between them adds another layer of complexity. Whether a subcontractor's charges to a GC are taxable depends on the nature of the work and the structure of the arrangements.
The capital improvement exemption certificate
When a contractor performs work that qualifies as a capital improvement, both parties benefit from using a capital improvement exemption certificate — Form ST-124. The property owner completes the form and gives it to the contractor, certifying that the work is a capital improvement. The contractor retains it as documentation supporting the decision not to charge sales tax on the job.
Contractors who perform capital improvement work but do not obtain completed ST-124 certificates are in a vulnerable position in an audit. Without the certificates, auditors may challenge the capital improvement classification on any given job and assess tax on the full contract price. Maintaining a complete file of ST-124 certificates for all capital improvement work is an essential practice for any contractor in New York.
For information about the Certificate of Authority required to collect sales tax in New York, see our guide at NYS Certificate of Authority.
How DTF auditors examine contractor businesses
When the DTF audits a contractor, the examination typically focuses on several areas. Auditors will review all contracts and invoices for the audit period and evaluate whether each job was correctly classified as capital improvement or RMI. They will look for jobs where no sales tax was charged and examine whether that treatment was justified.
Auditors will also review purchasing records to determine whether the contractor paid sales tax on materials appropriately — neither overpaying on exempt purchases nor underpaying on taxable ones. They will look for subcontractor payments and examine how those relationships were structured for sales tax purposes.
The audit period is typically three years, and auditors will frequently propose to extend it if they find significant issues in the initial period examined. A contractor facing an audit with significant classification issues in the first year reviewed should expect the auditor to request additional years.
Long Island contractors: a note on local enforcement
Contractors based in Nassau County and Suffolk County — and those doing significant work in the New York City boroughs — should be aware that both the DTF and local jurisdictions are active in monitoring contractor compliance. The volume of construction activity on Long Island and in the metro area means contractors here receive more than their proportional share of audit attention.
For Long Island contractors in particular, having clean records and clear documentation for every job classification is not optional — it is the baseline standard for operating in this market.
What to do if you receive a sales tax audit notice
If you receive a DTF audit notice, the first thing to do is not respond to the auditor directly. Contact a New York sales tax attorney before any communication with the Tax Department. The positions you take and the records you produce in the early stages of an audit significantly affect the direction and outcome of the entire examination.
For a broader overview of the NYS sales tax audit process, see our guide to NYS sales tax audits.
Why work with an experienced New York sales tax attorney
NYS sales tax matters are not like federal tax issues. The New York State Department of Taxation and Finance has its own procedures, its own auditors, and its own enforcement playbook — and it moves aggressively. For contractors specifically, the capital improvement vs. RMI distinction requires deep knowledge of New York sales tax law and DTF audit practice — this is not an area where general tax advice is sufficient. Here is what an experienced New York sales tax attorney brings to the table:
Deep knowledge of DTF audit procedures. We know how auditors are trained, what indirect methods they use, and where their assessments can be challenged. Generic tax help is not enough here.
Direct negotiation with the Tax Department. We communicate with DTF on your behalf from day one — protecting you from making statements that can be used against you and positioning the case correctly from the start.
Personal liability protection. NYS sales tax is a trust fund tax. If your business owes it, the state can — and will — pursue you personally. An attorney can identify and limit that exposure before it becomes a personal financial crisis.
Knowledge of every resolution option. From installment agreements to the Voluntary Disclosure Program to formal appeals — we know which path fits your situation and how to negotiate the best possible outcome.
Local presence, statewide reach. Our practice is based on Long Island and focused exclusively on New York tax problems. We are not a national call center. When you work with us, you work with an attorney who knows New York State tax law from the inside.
Speak with a New York sales tax attorney
If you are dealing with a New York contractor sales tax audit or a question about your home improvement business's sales tax obligations, do not wait for the situation to escalate. The sooner you have representation, the more options you have.
Contact our office to speak directly with a New York sales tax attorney. While our office is based on Long Island, we represent businesses and individuals facing NYS sales tax problems throughout New York State — from New York City and the Hudson Valley to Westchester, the Capital Region, and beyond. Call us or use the contact form at Tax Problem Law Center to schedule a consultation.