Trades

Bookkeeping by trade.

I keep books for trades businesses across the greater Seattle area, and every trade breaks the books in its own way. These pages cover four of them in detail: how each is licensed, what L&I charges for an hour of it, and where its books most often go wrong.

2,021

Electrical, plumbing, HVAC and roofing businesses in King County.

91%

Of those four trades in Washington are LLCs or corporations.

4×

The gap between the lowest and the highest L&I rate among them.

Fig. 01Trade contracting businesses in King County

Electrical1,082

Plumbing488

Roofing283

HVAC168

Active contracting businesses with a King County address on the Washington State L&I contractor register, 2026.

Trades

Trade by trade.

Each page covers what is particular to one trade: the licence, the L&I rate for an hour of its work, the job-costing traps and the cash patterns. The bookkeeping underneath is the same careful monthly work for all of them.

$1.4370 / hour L&I

Electrical

Copper that moves between the bid and the purchase, permits that follow the city line, and retainage held back on progress-billed work.

$1.8222 / hour L&I

Plumbing

Service and construction run as two businesses under one name, flat rates that bet on the clock, and parts riding around on the trucks.

$1.9751 / hour L&I

HVAC

A heating-heavy season, maintenance agreements paid a year in advance, and equipment that can be the largest cost on the job.

$5.7930 / hour L&I

Roofing

The highest L&I rate of the four, a season set by the rain, and insurance jobs paid by two parties in three instalments.

Every other trade

Another trade?

General contractors, painters, landscapers, concrete crews and the rest of the trades share the same core: jobs that need costing, accounts that need reconciling and filings that need clean numbers. Ask and I will tell you straight whether I am the right fit.

Side by side

Four trades, four sets of rules.

The licence, the bond and the hourly L&I rate all change from one trade to the next, and so does the place where the books most often slip.

Fig. 02Four trades, four sets of rules

Swipe to compare every trade →

ElectricalPlumbingHVACRoofing

Held with L&IElectrical contractor licencePlumbing contractor licenceSpecialty contractor registrationSpecialty contractor registration

Bond$4,000$6,000$15,000$15,000

L&I risk class0601030603070507

L&I rate per hour, 2026$1.4370$1.8222$1.9751$5.7930

One full-time worker, a year$2,759$3,499$3,792$11,123

Where the books usually slipMaterials and retainageService and construction blendedPrepaid agreementsInsurance jobs and the wet season

L&I 2026 base rates at an experience factor of 1.0; L&I counts a full-time year as 1,920 hours. Bonds from RCW 19.28, RCW 18.27 and L&I’s plumbing contractor requirements, checked September 2026.

Services

The same three services, whatever the trade.

Monthly bookkeeping, catch-up and cleanup, and QuickBooks setup and training. No payroll, no tax prep, no audits.

Every trade also files under the rules of the cities it works in.

Book a free consult

Tell me where the books stand.

Fifteen questions about your business and your books. I read every one personally and reply with a straight answer.