Plumbing Overhead: How Much Is Too Much?

A plumbing business can run strong margins on every job and still produce weak profit at the bottom of the P&L, and when that happens the answer is almost always overhead. Overhead is the cost of being in business rather than the cost of doing any particular job, and because it never attaches to specific work, it grows in ways job costs don't.

A truck payment, another software subscription, an office hire, a storage unit for material, and over a couple of years the fixed cost base has crept up to where it's consuming margin that should have been profit.

Nothing announces this while it's happening; it just shows up as year-end numbers that are weaker than the work deserved.

This post covers how to tell whether your plumbing overhead is too high, what healthy overhead looks like as a percentage of revenue, and where to look first when overhead is the gap between good jobs and a good bottom line.

For the broader picture of plumbing profitability, see Plumbing Profit Margins: What's Normal for a Plumbing Business?.

For how overhead should be organized in your books so it's actually measurable, see Plumbing Chart of Accounts Setup in QuickBooks.

What counts as overhead

Before judging whether overhead is too high, you need a clean definition of what belongs in it, because miscategorization is the most common reason plumbing owners misread their own numbers.

Overhead is everything that keeps the business running but can't be tied to a specific job: office rent and utilities, administrative payroll, software, general marketing, professional services, business insurance that isn't job-specific, licensing and continuing education, the fixed portion of vehicle costs like truck payments, insurance, and registration, and owner compensation. What overhead is not is the direct cost of doing work. Materials, fixtures, burdened crew labor, permits, and the variable vehicle costs like fuel and maintenance that scale with job volume all belong in cost of goods sold, where they're measured through gross margin.

The line matters because when it's blurry in either direction, your overhead percentage stops measuring what you think it measures. Variable job costs dumped into overhead make your gross margins look better than they are while inflating apparent overhead. Real overhead buried in job costs does the reverse. Either way, every judgment built on the number is compromised, which is why the chart of accounts structure is the foundation for this whole analysis.

What a healthy overhead percentage looks like

With overhead cleanly separated, you can measure it against revenue and compare to general ranges, remembering these are guides shaped by your size and model rather than hard rules.

For plumbing businesses doing $500,000 to $2 million in revenue, overhead commonly runs 18 to 28 percent of revenue.

Smaller operations tend toward the higher end because fixed costs like insurance, software, and basic administrative infrastructure don't shrink proportionally with revenue, so they eat a bigger share of a smaller base.

For plumbing businesses doing $2 million to $5 million, overhead commonly runs 15 to 22 percent, as scale starts spreading the administrative infrastructure across more revenue.

Above roughly 30 percent of revenue, something is usually structurally off and worth a hard look. Not automatically a crisis, since there are legitimate temporary reasons overhead runs high, but a number in that territory is a signal to investigate rather than accept.

One nuance specific to plumbing worth noting is that businesses weighted toward new construction sometimes show lower overhead percentages simply because the revenue base is inflated by high-material, thin-margin work.

A new-construction-heavy shop at 16 percent overhead isn't necessarily leaner than a service shop at 24 percent, because the denominator is doing different work in each case.

This is another reason margin analysis and overhead analysis need to happen together rather than in isolation.

Why the percentage alone isn't the answer

The benchmark tells you where to look, but overhead that's too high isn't simply overhead above a number. The real question is whether each piece of overhead produces a return, because overhead exists to make the business run better, not merely to exist.

Two plumbing companies can both run 25 percent overhead. In one, that includes a dispatcher who keeps the schedule tight and the trucks routed efficiently, an office manager who keeps collections current, and marketing that reliably produces booked calls.

That overhead is earning its keep.

In the other, the same 25 percent includes an underused admin hire, overlapping software nobody fully uses, a storage unit nobody has visited in months, and ad spend that's never been measured against the jobs it produced.

Judging overhead purely by the ratio misses this. A slightly elevated percentage that's driving efficiency and growth can be healthy, and a lean-looking percentage full of waste can be a real problem. The number tells you whether to look, but what you find determines what to do.

Where plumbing overhead bloat usually hides

When overhead has crept too high, the cause usually sits in one of a few places.

Administrative payroll is the most common. Office headcount added during a busy stretch rarely gets revisited when volume normalizes, so the business carries more admin cost than current revenue supports. Checking whether administrative staffing matches today's revenue rather than your busiest quarter is usually the highest-value single audit.

The software stack is second. Field service platforms, accounting tools, dispatch and routing apps, marketing subscriptions, and phone systems accumulate, and businesses routinely pay for overlap or unused seats. A line-by-line pass over every recurring charge almost always finds cuts.

Vehicles and storage are third, and plumbing is prone to both.

Trucks carry substantial fixed cost, and fleets tend to grow with optimism rather than with utilization.

A truck that isn't running full weeks is fixed cost without matching revenue.

The same goes for warehouse or storage space rented for material convenience that job volume no longer justifies.

Owner compensation is fourth and the most delicate.

If owner pay has grown past what the business supports at its size, it distorts the overhead picture and hides whether the underlying operation is healthy.

A business that only looks profitable because the owner underpays themselves, or only looks bloated because the owner overpays themselves isn't giving you a true read in either direction.

Unmeasured marketing is fifth. Marketing is legitimate overhead only when it produces jobs you can trace. Spend that can't be connected to booked work is the easiest cut available, because you can't prove you're giving anything up.

How to run the diagnosis

The practical evaluation is three passes, all dependent on clean books.

First, the trend. Pull overhead as a percentage of revenue for the past two or three years. Climbing steadily is the clearest warning, because it means fixed costs are growing faster than revenue and compressing profit. Stable or declining as you grow is the healthy pattern.

Second, the category audit. Break overhead into its groups and ask what each produces. This is where productive versus unproductive gets concrete, category by category, rather than a verdict on the total.

Third, the benchmark check. Compare your percentage to the ranges for your size. Well above range confirms there's something to find, and the first two passes tell you where.

If your books don't separate overhead from job costs, or your overhead is one undifferentiated lump, none of the passes produce reliable answers. That's not a reason to skip the analysis. It's the reason to fix the books first.

Cut, or grow into it

When the diagnosis confirms overhead is genuinely high, there are two fixes, and choosing correctly depends on what the audit found.

If the audit surfaced waste, cut it. Unused software, excess admin capacity, idle vehicles, unmeasured marketing, and storage nobody needs all come out without giving up anything that was working.

If the overhead is productive but revenue hasn't caught up to it, the fix is growth rather than cuts.

A business that invested ahead, building dispatch capacity, office support, and infrastructure for the operation it's becoming, will show elevated overhead percentages until revenue fills in. Cutting productive capacity in that situation dismantles the growth you built it for.

Getting this wrong is expensive in both directions, which is the entire point of auditing by category instead of reacting to the total. The audit tells you which situation you're actually in.

Where this connects to the books

Every step of overhead analysis rests on bookkeeping quality. You can't measure the percentage without overhead cleanly separated from job costs, can't audit categories that don't exist in your chart of accounts, and can't track a trend across books that weren't structured consistently.

The overhead question is a management question sitting on top of a bookkeeping question, and the analysis is only as good as the structure underneath.

At Prophet Accounting, we work with plumbing contractors and other home service trades across Port St. Lucie, the Treasure Coast, and nationwide.

We structure books so overhead is separated from job costs and organized into categories you can actually evaluate, which turns overhead analysis from guesswork into a routine review.

If your jobs earn well but the bottom line doesn't show it, overhead is the first place to look.

Schedule a consultation at prophetaccounting.com/contractors or give us a call at (772) 380-2871.

For a quick read on monthly bookkeeping costs, our pricing calculator gives you a ballpark in about two minutes.