The short answer
For self-employed plumbers, potential business expenses include fittings and pipe, tools and equipment, and business insurance. The business purpose, personal-use share, records, and type of purchase determine whether and when a cost is deductible.
What can you write off?
The purchase needs to make sense for your work. Under the federal rules, a business expense generally needs to be ordinary and necessary: common and accepted in your field, and helpful and appropriate for the business. Personal spending stays personal. IRS: business income and expenses.
- Fittings and pipe
- Pipe and fittings bought for jobs need receipts and records of how they're used.
- Tools and equipment
- Durable tools and equipment may involve depreciation or an eligible expensing election.
- Business insurance
- Business insurance needs a documented connection to your plumbing work.
These are examples to review, not a list of automatically approved deductions. The right category and timing matter, too. IRS: Tax Guide for Small Business.
The bit worth a second look.
Stock in the van and materials installed on a job may need different tracking. Use a consistent method rather than deducting the same purchase twice.
A lasting piece of equipment can follow different rules from a consumable supply. Its business use, when it goes into service, and any applicable expensing election affect the deduction. Keep the invoice and details instead of guessing from the price. IRS: depreciation and equipment.
Give the receipt a little context.
A bank statement shows money moved. An itemized receipt helps explain what you bought. Keep both when they support the expense, along with the date, amount, seller, and business purpose. IRS: records to keep.
For example, label a purchase of fittings and pipe with the job, client booking, or business activity it supported. If the basket also contains something for home, mark the work items and keep a record of the split. Future you has a lot to remember already.
With WorkMade, scan the receipt and review the business items it identifies. Match it to the transaction or add an entry, then keep the supporting details together. A suggestion still needs your business context.
A write-off isn't a refund for the whole purchase.
An eligible deduction generally reduces taxable business profit. It doesn't mean the government pays you back the price on the receipt. The tax effect depends on your wider situation. Buy something because the business needs it, then keep the records that support its treatment. IRS: Tax Guide for Small Business.
Sources & scope
Written by WorkMade for US independent businesses. Federal tax guidance focuses on sole proprietors and single-member LLCs taxed as sole proprietors. Employee work, other entity types, state taxes, payroll, and regulated businesses can need different treatment. Examples are educational and depend on your circumstances.
Sources checked September 18, 2026. IRS annual publications may carry an earlier tax-year label; use the applicable year's rules for your return.




