FREE BUSINESS OWNER GUIDE

Your Plumbing Business Is Busy—but Which Jobs Actually Make Money?

To understand plumbing job profitability, record the invoice amount and direct costs for each job—materials, applicable technician labor, subcontractors, and other traceable costs. Subtract direct costs from job revenue to estimate gross profit, then remember that overhead and other expenses still need to be covered.

What you'll learn

Understand the issue, follow a practical process, and leave with a checklist you can use this week. No email required.

Why should you care?

Imagine your plumbing company has enough customer demand to justify two more service vehicles, additional equipment, and another crew. Before making that commitment, you need to understand which jobs consistently contribute enough margin to support new wages, vehicle payments, and operating expenses. If certain services are underpriced or regularly exceed estimated labor hours, expanding them could magnify the problem. Reliable job-cost records help you evaluate growth opportunities and may also help explain your business performance to a future lender or buyer.

Revenue alone does not tell you which jobs work

A plumbing business can have a busy schedule and still struggle with margin if materials, labor, return visits, and subcontractor charges are not tracked consistently. Job costing compares revenue from a job with costs assigned to that job. The categories and allocations should fit your operations.

Start with a basic job-cost worksheet

For each job, record job ID, customer, invoice amount, materials, technician hours and applicable labor cost, subcontractors, and other direct costs. Keep overhead separate unless you have a consistent allocation method. Track change orders and warranty return visits so costs do not disappear.

Example: a water-heater installation

The customer is billed $2,400. The water heater and fittings cost $900, direct labor $450, and a disposal subcontractor $100. The tracked direct cost is $1,450 and gross profit is $950, about 39.6%. This is not net profit: insurance, trucks, marketing, office salaries, and other expenses remain.

Three questions your numbers can answer

Which job types consistently require unbilled return visits? Are material costs rising faster than your prices? Are quoted labor hours close to actual hours? You need consistent data before making pricing changes based on a single job.

Try a two-week test

Choose ten completed jobs. Collect invoices, supplier receipts, and labor hours. Calculate direct costs and gross profit for each. Mark missing data instead of inventing estimates. Review patterns with the owner and appropriate advisers.

Step by step: put this into practice

Give every job an ID — Use a consistent identifier across estimates, invoices, technician time, supplier receipts, and change orders.
Capture materials and returns — Record parts used, supplier credits, and return trips. Avoid treating every material purchase as a cost of the same job without checking usage.
Track technician time — Use actual hours where possible. Decide how to calculate direct labor cost consistently, including applicable payroll-related components.
Add subcontractors and other direct charges — Include job-specific third-party work and clearly attributable direct costs. Keep company-wide overhead distinct unless you have a consistent allocation method.
Review patterns, not one-off results — Compare similar job types and look for recurring unbilled hours, warranty callbacks, and estimate-versus-actual differences.

See how the numbers work

Illustrative water-heater installation: Customer invoice $2,400; heater and fittings $900; direct labor $450; disposal subcontractor $100. Tracked direct costs are $1,450, leaving $950 gross profit (about 39.6% gross margin). That is not $950 in take-home profit: trucks, insurance, marketing, office wages, taxes, and other expenses still matter.

What you can do today

Choose 10 completed jobs
Gather invoices, material receipts, and labor hours
Calculate direct cost and gross profit for each
Flag callbacks, discounts, and missing costs
Compare similar jobs before changing prices

Frequently asked questions

Should truck expenses be charged to each job?

It depends on the reporting method. If you allocate them, use a consistent documented approach rather than assigning costs arbitrarily.

What if technicians do not track their hours?

Start with a simple time-entry habit for a two-week test. Estimates can be useful for planning but should be distinguished from actual hours.

Does gross margin tell me whether I have enough cash?

No. Gross margin measures a form of profitability; collections, bills, debt payments, and timing affect cash.

Need a second set of eyes on your books?

If you would like help organizing your records or discussing a bookkeeping issue, CERTALION can review your needs and explain potential next steps. You can also subscribe to the CERTALION Business Brief for more free educational resources.

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Educational information only; not legal, tax, or financial advice. Examples are illustrative. CERTALION is not a CPA firm and does not provide audits, financial statement reviews, attest services, or independent assurance. Service availability and scope must be confirmed before engagement.