How do you outsource bookkeeping as a mechanical contractor

Short answer: get your service work and your project work separated in the books first, then hand over the day-to-day stuff. Transaction entry, reconciliation, supplier bills, service invoicing, progress billing prep. You keep approvals, signatures, and anything your CPA should be touching.

The separation part is what most people skip, and it is why outsourcing goes badly for mechanical contractors more often than for other trades.

Why your books feel like two different businesses

Because they basically are.

You have a service side. Calls coming in daily, flat rate or T&M, money in within a week or two, parts coming off the van. High volume, short cycle.

Then you have a project side. Progress draws, retainage held back, costs piling up against a budget for six months before anyone knows how the job went. Low volume, long cycle.

Same company, same EIN, completely different rhythms. Most bookkeepers set you up properly for one of them and let the other quietly turn into a mess. Usually the project side, because service is louder and gets attention.

The part that hurts: when both sides sit in the same set of accounts, your service department’s cash quietly covers your project department’s overruns. You will not notice until year end, and by then you have repeated the same mistake on three more jobs.

Start with two P&Ls

Before you talk to anyone about outsourcing, set up a class, department, or division split in your accounting software. Every transaction needs to land on one side or the other.

This is on you, not your bookkeeper. They code to whatever structure exists. They cannot invent one from a pile of receipts.

It takes an afternoon. It is the highest-value afternoon in this whole process.

What your bookkeeper is walking into

Worth knowing what makes your books harder than a regular small business:

• Maintenance agreements. Billed in January for the whole year, but the revenue belongs across twelve months as the visits actually happen
• Truck stock. Parts sitting on vans, getting consumed on calls, needing to reconcile against what you bought
• Flat rate versus actual. What you billed against what the call actually cost you in labor and parts
• Warranty callbacks. Real labor and real parts, zero revenue. If it is not coded separately you will never know what warranty costs you
• Techs crossing sides. Same guy on service calls Monday, on a project Tuesday. That payroll has to split
• Trucks and equipment. Depreciation, and ideally cost per truck
• Progress billing and retainage on the project side
• Certified payroll if you touch public work

Get the software sorted first

You are almost certainly running a field service platform feeding into accounting software. ServiceTitan, BuildOps, Housecall Pro, something similar, syncing into QuickBooks or Xero.

Before anyone starts, get clear on:

• Which system is the source of truth for service revenue
• How invoices sync, and what happens when one fails
• Whether POs flow through from the field platform
• How tech time gets from timesheets into payroll and job cost
• Who is responsible when a sync breaks

That last one causes more problems than anything else on this list. Failed syncs mean work you did and never billed. Decide who owns catching them before day one, not after you find three unbilled calls from last month.

Clean up what is already there

Do not hand someone a backlog and expect reports in week one. It does not work and it sours the relationship immediately.

If you are behind, run a bookkeeping cleanup first. Months or years behind, catch-up bookkeeping is its own separate job. Get it done, then start monthly work from a clean month.

For mechanical contractors, cleanup almost always turns up the same three things. Parts purchases never matched to a job or call. Service and project revenue dumped into one income account. Maintenance agreement money recognized all at once instead of spread across the year.

Decide who does what

Give to your bookkeeper:

• Daily transaction entry, coded to service or project and to the job or work order
• Weekly bank reconciliation
• Supplier invoices entered and matched to POs
• Parts and material coded to the right call or job
• Chasing unbilled service calls
• Deferred revenue schedules for maintenance agreements
• Progress billing prep, including G703 line items
• Retainage tracking by job
• Payroll prep with the service and project split
• Certified payroll prep on prevailing wage work
• 1099 and W-9 tracking
• Monthly reports: service P&L, project P&L, job cost, AR aging

Keep for yourself:

• Approving payments and purchases
• Signing pay applications and certified payroll statements
• Pricing and flat rate book updates
• Credit terms, and deciding when to stop work for someone

Leave with your CPA:

• Tax returns and planning
• Depreciation elections on trucks and equipment
• Financial statements for bonding or lending
• Revenue recognition method

Worth saying plainly: a bookkeeper does not file your taxes, does not issue audited financials, and is not a CFO or controller. Anyone selling you a bookkeeper as a substitute for your CPA is overselling.

Where to find one

Freelance

Cheapest option. You do the vetting and the managing, and very few freelancers have dealt with a field service platform syncing into accounting software.

Local accounting firm

Good on tax. Usually priced well above what daily transaction work justifies, and your service department generates a lot of daily transactions.

Managed service

Dedicated bookkeeper, and the provider handles vetting, training, quality checks, and replacement if it does not work out. Costs more than a freelancer. You are not the one managing them, which is the whole point.

More detail on the trade-offs in this guide to outsource bookkeeping services.

Questions worth asking before you hire

A normal bookkeeping interview will not tell you much. These will:

• We bill an annual maintenance agreement in January. How do you handle the revenue?
• A tech does three service calls and four hours on a project in one day. How does that payroll get coded?
• An invoice fails to sync from the field platform. How do you catch it?
• How would you track parts pulled off a truck against a work order?
• A callback is warranty work, no revenue. How do you code the labor and parts?
• Have you worked with a contractor running service and projects together?

You are not looking for textbook answers. You are finding out whether they have seen this before or are about to learn it on your books.

The first two weeks

Week 1

Give them access to everything: accounting software, field platform, bank feeds, payroll. They sit behind you through a full week of service invoicing and one supplier payment run, writing down how each works.

Week 2

They do it, you check everything before it leaves.

From week three, a daily end-of-day summary and fifteen minutes with you once a week is usually enough. Supplier invoice volume is where things pile up first, and accounts payable outsourcing covers how to set that rhythm properly.

Check in at 30 days

Run through this list:

• Service and project revenue in separate P&Ls?
• Everything reconciled through last month?
• Any invoices that failed to sync and never got billed?
• Maintenance agreement revenue recognizing monthly?
• Tech labor splitting correctly between service and project?
• Unbilled service work being chased every week?
• Do the job cost numbers match what you actually believe about those projects?

Miss three or more and the problem is usually the structure you set up at the start, not the person doing the work.

What it costs

Depends on transaction volume, how many techs, how many active projects, how many bank accounts, and whether you need cleanup first. Mechanical contractors usually run heavier transaction volume than their revenue suggests, because service work generates so many small ones.

Wishup pricing for a dedicated bookkeeper is $999/month part-time at 4 hours a day and $1,799/month full-time at 8 hours a day. Cleanup gets quoted separately.

Part-time is fine if you are mostly service with a few projects running. Go full-time once you have several projects going at once, prevailing wage payroll, or more than a handful of techs.

If you would rather skip most of this

Everything above assumes you are going to find, vet, and onboard someone yourself. That is genuinely the better route if you have the time, because you end up with exactly the setup you want.

If you do not have the time, a managed service does the finding and vetting for you. Wishup places pre-vetted bookkeepers who work inside your existing accounting and field service software, with onboarding taking about an hour. You still have to do the two P&Ls and the software decisions, since nobody can make those for you. Everything after that is handled.

Each engagement comes with a dedicated account manager, a manager behind the bookkeeper, end-of-day reports, and a quick replacement if the person is not a fit.

If you want to see how this works for a specific trade first, there are pages on bookkeeping services for HVAC businesses and bookkeeping for plumbers. Or hire a virtual bookkeeper and talk through your service and project split on a free call.

Frequently asked questions

Should service and project work be on separate books?

Not separate books. Separate classes or departments inside one set. One tax return, two P&Ls. Separate legal entities is a different conversation and one for your CPA.

Can a bookkeeper handle my maintenance agreement revenue?

Yes. They build the deferred revenue schedule and run it monthly so the money spreads across the year instead of landing in one month.

Who fixes failed syncs between my field platform and accounting software?

Your bookkeeper can catch them and re-enter manually, which is the usual arrangement. Fixing the integration itself is an IT or software job. Agree who does which upfront.

Can a bookkeeper track truck stock?

They can track what you bought and code what got consumed against work orders. A proper physical count on every van is an operations process you run, not a bookkeeping one.

How long before this actually works?

Two weeks of supervised work, about a month before you can fairly judge it. Add cleanup time on top if you are behind.