Top 5 Bookkeeping Mistakes That Cost Trade Businesses Thousands

For plumbers, electricians, HVAC techs, landscapers, and other field service pros trying to keep their finances under control without drowning in admin.

Running a trade business is tough enough without having to worry about whether your books are in order. But for many blue-collar business owners, bookkeeping is an afterthought — until tax time hits, or cash flow dries up. The truth is, most small trade-based companies lose thousands every year simply due to basic accounting mistakes.

Here are five of the most common issues I see — and what you can do to fix them.

1. Mixing Personal and Business Expenses

This is the #1 mistake among solo contractors and small teams. You grab lunch, fill up your truck, or buy supplies at Lowe’s — and it all goes on the same credit card. Later, your bookkeeper (or you) has to dig through and figure out what was business vs. personal.

Fix it:
Open a dedicated business checking account and debit/credit card. Only run business expenses through that account — no exceptions.

2. Not Categorizing Expenses Correctly

You might be entering everything into QuickBooks — but if you’re putting fuel, tool purchases, payroll, and subscriptions all under “General Expense,” your reports are useless.

Fix it:
Use clear, consistent categories. For example:

• Materials & Supplies

• Vehicle Fuel & Maintenance

• Subcontractor Labor

• Job Costs

• Marketing

• Office Expenses

You’ll immediately see where your money is going — and where it’s leaking.

3. Falling Behind on Reconciliations

Reconciling means matching your books to your bank and credit card statements. If you’re not doing this monthly, you’re likely missing transactions, duplicating entries, or letting fraud slip through.

Fix it:
Block out time monthly (or hire help) to reconcile every account. It usually takes less than an hour and avoids massive errors.

4. DIY Bookkeeping Without Oversight

Lots of tradespeople DIY their books using Excel, apps, or QuickBooks. But unless someone checks your work — mistakes build up fast.

Fix it:
Even if you handle the basics yourself, have a bookkeeper review your books quarterly or annually. They’ll catch errors, keep you tax-ready, and reduce your liability.

5. Not Tracking Job Costs by Project

If you don’t know what you made (or lost) on each job, you’re flying blind.

Fix it:
Track materials and labor by job using software like QuickBooks Projects, Jobber, or Housecall Pro. Know your real profit per job — not just your bank balance.

Need a Hand Fixing Your Books?

Whether you’re months behind or just want a second set of eyes, we specialize in bookkeeping for trade businesses like yours — electricians, plumbers, landscapers, HVAC, and more.