Plumbing Bookkeeping: What to Track and Why

If you run a plumbing business, you already know the work is unpredictable. Emergency calls at 2 AM, scheduled installs that run over because of a hidden leak, service calls that turn into full repipes, and commercial jobs that stretch across weeks. Every day looks different.

What doesn't change is the need for clean books that actually tell you how your business is performing. And for most plumbing contractors, the books are the last thing on the list at the end of a long day.

Here's what plumbing bookkeeping should look like, and why it matters more than most owners realize.

Why Plumbing Bookkeeping Is Different

Most bookkeepers treat a plumbing company the same way they'd treat any other small business. Categorize expenses, reconcile accounts, and hand off a P&L at tax time. That's fine if you just want a tax return. It's nowhere close to enough if you want to actually run the business.

Plumbing has specific financial characteristics that generic bookkeeping misses entirely.

Revenue comes from multiple streams that behave very differently. Service and repair calls have quick turnover, small invoices, and typically solid margins. New construction work has longer timelines, larger invoices, and thinner margins because of the labor and materials involved. Maintenance contracts generate steady recurring revenue that stabilizes the whole business. Commercial work is a different animal entirely, with longer payment cycles and different job structures.

If your bookkeeper lumps all of this into one revenue line, you have no way to see what's actually driving your business. A $90,000 month that was mostly commercial install work looks nothing like a $90,000 month that was mostly service calls, but your P&L won't tell you that unless it's structured properly.

Parts and inventory are a real factor. You're stocking trucks with fittings, valves, fixtures, and common repair parts. You're buying materials for specific jobs. The tracking matters because material costs are usually 25 to 35 percent of your job cost on installs, and if you're not seeing them clearly, you can't price jobs accurately.

Labor is your biggest cost. In Florida and across the Treasure Coast, a journeyman plumber with benefits is running somewhere between $30 and $45 per hour loaded. If a two-man crew is on a job for eight hours, that's $480 to $720 in labor before any materials hit the books. Not knowing this in real time means you're pricing jobs based on guesses instead of numbers.

Job Costing for Plumbing Contractors

Job costing is the single most important thing you can do with your books. It means every dollar of revenue and every dollar of cost gets tied to a specific job.

In QuickBooks Online, you do this through Projects. Create a project for every install, repipe, or any job that's bigger than a one-hour service call. Tag the invoice, the parts, the labor hours, and any subcontractor costs to that project. When the job is done, you pull the profitability report and see exactly what you made on it.

For service calls, you don't need to create a project for every single one. You can batch them by week or by tech so you can still see service revenue and service costs without drowning in administrative work. The goal is visibility, not busy work.

We break down the full setup in How to Track Job Costs in QuickBooks Online. The mechanics work the same for plumbing as they do for any other trade.

Without job costing, you're making pricing decisions based on gut feel. A contractor who's been in business for 20 years can probably guess margins within 10 percent. Everyone else is flying blind. And even the experienced contractor is usually wrong about which types of jobs are really making the money.

Revenue: Break It Out by Service Type

Your revenue should not be one line on the P&L. Break it into categories that reflect how the business actually operates.

Service and repair revenue is your quick-turn residential and commercial repair work. Drain clearings, leak repairs, fixture replacements, water heater swaps. Small tickets, fast collection, and good margins.

New construction and install revenue is the larger project work. New water heaters with full install, repipes, bathroom remodels, and new construction plumbing. Bigger invoices and longer jobs, but thinner margins because of labor and materials.

Maintenance and recurring revenue is anything tied to a recurring service agreement. Annual water heater flushes, quarterly drain maintenance, any ongoing service contract.

Commercial revenue if you do any meaningful volume of commercial work. Commercial jobs behave differently from residential on every dimension, from billing to payment cycles to job complexity. Worth tracking separately.

When your revenue is structured this way, your P&L starts telling you a story. You can see that service work is 60 percent of revenue but 75 percent of your gross profit. Or that your install work looks big on the top line but is barely breaking even once you factor in the full cost. That's the kind of information that changes how you run the business.

Cost of Goods Sold: Three Lines

COGS for a plumbing business should be broken into three sub-accounts. This is the same structure we use for every contractor we work with.

Materials and parts covers everything you buy that goes into a job. Pipe, fittings, fixtures, water heaters, valves, solder, flux, etc. The stuff that either lives on the truck for service calls or gets ordered for specific installs.

Direct labor is your plumbers' wages while they're working on jobs, plus the burden costs (payroll taxes, workers comp, health insurance, PTO). This is usually your biggest cost line and the one that moves the most.

Subcontractor costs is anything you sub out. Drain cleaning specialists for complex backup jobs, excavation for underground repairs, or electrical work for tankless water heater installs. Keep these separate from your direct labor so you can see them clearly.

When you have these three lines plus revenue broken out by type, you can calculate actual gross profit by service line. That's the foundation for every pricing decision, every hiring decision, and every capacity decision you'll make.

For a deeper look at structuring this, check out How to Set Up Your Chart of Accounts as a Contractor.

Managing Cash Flow in a Plumbing Business

Cash flow in plumbing is tricky for a few reasons.

Service work collects fast. Someone calls with a clogged drain, you fix it, they pay on the spot or within a few days. That's great for cash flow.

Install work collects slower. A $15,000 water heater install might have a partial deposit up front, the balance due on completion, and another week or two for the check to clear. Meanwhile you've already paid for the equipment, the labor is out the door, and you're floating the costs.

Commercial work collects slowest of all. Payment terms of net 30, net 45, or longer are common. You do the work in February and get paid in April. If you're not managing this carefully, you end up revenue-rich on paper and cash-poor in the bank.

Good bookkeeping includes a forward-looking cash flow view. Not a complicated spreadsheet, just a clear picture of what's collected, what's outstanding, and what's coming due in the next 90 days. When you can see the gaps coming, you can plan for them. When you can't, you end up surprised.

Here in Port St. Lucie and across the Treasure Coast, we see plumbing contractors who look busy and profitable on the surface but are scrambling to cover payroll because their AR is sitting at 45 or 60 days. That's almost always a structural issue with how AR is being managed, not a business performance issue.

Tracking Parts Inventory Without Losing Your Mind

Plumbing businesses have more inventory complexity than most trades. You're carrying parts on every truck. You're ordering materials for specific jobs. You're stocking commonly used items in the shop or warehouse.

The temptation for most owners is to do one of two things. Either track nothing and just expense everything as it comes in, or try to track everything down to the last compression fitting. Both approaches fail.

Here's the middle path that actually works.

For truck stock and commonly used consumables, expense them when purchased. Don't try to track every elbow and every valve. The tracking cost is higher than the information value. Accept some noise in your P&L and move on.

For job-specific materials, track them to the project. When you order a water heater for a specific install, tag it to that project. Same for fixtures for a bathroom remodel, or pipe for a repipe job. This gives you real cost tracking on the work that actually matters for profitability.

For larger items with real resale value (stocked water heaters waiting on installs, expensive fixtures ordered in bulk), you might treat them as inventory on the balance sheet until they're used. But most plumbing businesses under $5 million in revenue don't need to go that deep. Expense-as-purchased works for most items.

Common Plumbing Bookkeeping Mistakes

Lumping service and install revenue together. These have completely different margins, different labor intensity, and different working capital needs. Mixing them hides the real story of your business.

Not separating labor costs by job. If all your crew's hours are flowing into a single labor expense account, you have no way to see which jobs were profitable and which ones were losers.

Ignoring small service call inefficiencies. A tech who takes 90 minutes for a job that should take 45 is costing you real money. Without job costing, you never see the pattern. With it, you can identify the problem and address it.

Mixing personal and business expenses. Every Amazon order, every meal, every truck charge that runs through the business inflates your costs and makes your margins look worse than they are. Separate accounts, separate cards, separate everything.

Waiting until tax time to reconcile. Three months of messy books is a weekend project. Twelve months is a reconstruction job that takes weeks and costs thousands extra.

Not tracking callbacks. When you have to send a tech back to re-do a job, that's labor cost with no additional revenue. If callbacks are frequent and nobody's measuring the cost, your margins are worse than your P&L shows.

We wrote about broader versions of these issues in Why Your Contractor P&L Is Lying to You. The fixes are the same for plumbing as they are for any other trade.

What to Look for in a Plumbing Bookkeeper

The right bookkeeper for a plumbing business needs to understand job costing, know how to structure a chart of accounts for a trades business, and be able to separate service revenue from install revenue in your reporting.

Most generic bookkeepers won't do this. They'll categorize your transactions, reconcile the bank account, and send you a P&L that technically balances but tells you nothing useful about how the business is actually performing.

At Prophet Accounting, we work exclusively with home service contractors in Port St. Lucie, across the Treasure Coast, and nationwide. We set up job costing, structure your chart of accounts for plumbing specifically, and deliver monthly reporting in plain English so you know exactly where your business stands.

If your books aren't helping you make decisions, schedule a consultation at prophetaccounting.com/contractors.