The deciding feature is whether the tool remembers the property, not the job. Gas certificates, backflow retests and drainage as-builts all attach to an address for years, and they have to be findable by address. Fergus was built by a plumber and holds gas certificates on the job. ServiceM8 wins on after-hours call-out volume. Pick on which half of your week is bigger.
Three trades, three licences, one van
A plumber, a gasfitter and a drainlayer are three separate registrations under the Plumbers, Gasfitters and Drainlayers Board, each with its own licence and its own annual renewal, and each held at certifying, tradesman or exemption level. One person can hold all three. A three-person shop can be carrying nine live licence lines, all expiring on their own dates, and every one of them decides what that person is allowed to sign off unsupervised.
That is a scheduling constraint no service-trade software models for you. When the dispatcher sends the tradesman-level gasfitter to a job that needs a certifying signature, the work still needs a certifying gasfitter to certify it, and the supervision chain has to be recorded. The nearest thing to a fix in any of the mainstream tools is skill tags on staff plus job types, set up by hand. Ask about that in the trial. Nobody sells it as a feature.
Gas work carries two certificates, not one
Gasfitting under the Gas (Safety and Measurement) Regulations 2010 produces a Certificate of Compliance under regulation 49, stating the work complies, and a Gas Safety Certificate under regulation 52B, verifying the connected installation is safe to use. WorkSafe sets both out, and the risk category of the work decides which apply. A certifying gasfitter signs, including for work done under their supervision.
Two documents per gas job, from two different regulations, is the single most useful thing to test a shortlist against. Fergus documents a certifications module covering gas certificates and producer statements held against the job, and Tradify publishes NZ gas safety certificate templates alongside its electrical ones. In ServiceM8 both are custom forms you build or import. That is workable, and it is also two evenings you spend building forms before you have logged a single job.
| Tool | What it does for plumbing and gasfitting | Pricing shape |
|---|---|---|
| Fergus | Gas certificates, compliance certificates and producer statements held on the job; over 100 supplier price books including Plumbing World, Mico and Corys | From $53 a month on Basic and $75 on Professional, with timesheet seats charged separately |
| Tradify | NZ gas safety certificate templates alongside the electrical set, signed and sent from the app | Per user, from $48 a month on Lite |
| ServiceM8 | Certificates as custom forms you build or import; the strongest dispatch and job-creation flow for reactive call-outs | By monthly job count with unlimited users, $29 to $349 a month |
| simPRO | Asset registers and a maintenance planner built for backflow rounds and contract servicing | Quote only, with no published price |
Backflow and drainage are calendars, not jobs
This is the part that catches shops moving off a spreadsheet. A backflow prevention device on a medium or high risk property has to be tested annually by an Independently Qualified Person, and the result goes to the council as a condition of the building warrant of fitness. That is a recurring obligation attached to a device at an address, running on its own anniversary, forever.
Drainage records behave the same way. The as-built goes to council, the council holds it against the property file, and the next person who digs there rings you for a copy. Both cases want the same thing: a record filed by property and device, with a date that comes back around on its own.
Every mainstream tool can create a recurring job. What varies is whether the recurrence carries the last test result, the device serial and the council reference with it, or just puts an empty job in next year's diary. simPRO's asset registers and maintenance planner are built for exactly this pattern and are the strongest of the four here, at the cost of being quote-only pricing and considerably more system than a domestic plumber needs. Fergus and Tradify will do it with recurring jobs plus attachments and some discipline about naming.
The after-hours call-out is where the money leaks
Worked example, a four-person plumbing and gasfitting shop in Christchurch that takes emergency work.
- Around 210 jobs a month, of which about 45 are after-hours call-outs.
- Call-outs get written on a phone note at 11pm and typed up the next morning. On the shop's own reckoning, about 6 a month never get invoiced at all, and another 10 go out with the after-hours rate missed.
- Six unbilled call-outs a month is 72 a year gone, before you count the 120 that went out underpriced.
- ServiceM8 at 210 jobs a month sits on the Premium tier at $149 a month, which is $1,788 a year, with unlimited users so the fourth person costs nothing extra.
- Divide one by the other. If the tool recovers all 72, it costs $24.83 per recovered call-out. If it recovers half, $49.67. If it recovers only a quarter, $99.33.
- Compare each of those against your own average call-out invoice. For most shops the third number is still comfortably profitable, and recovery is usually better than a quarter, because the job gets created when the phone rings rather than when somebody remembers.
Do that sum with your own figures rather than mine. The stack cost checker holds the ServiceM8 tiers and shows the annual bill against your job count, and the ServiceM8 pricing post has the job caps for every tier.
Merchant accounts and the materials list
Plumbing is a merchant trade. Plumbing World, Mico, Reece and Corys accounts, a van stock list, and a materials bill that arrives three weeks after the job it belongs to. Fergus integrates with over 100 suppliers and lets you carry two supplier price books plus custom ones, which is the difference between quoting from this month's prices and quoting from what you remember paying in autumn.
Test that on your own suppliers rather than on the logo wall. Ask the vendor to show you a live price book pull from the merchant you actually buy from, on a trial account, before you sign anything. A price book that covers three of your five suppliers is worth about half of what the sales call implied.
When you do not need software at all
A one-van plumber doing maintenance and small installs, invoicing through Xero within a day or two of the job, has no gap that a $53 a month subscription closes. The gas certificates go on the PGDB forms, the invoices go out of Xero, and the recall list is a phone. That works well up to about 60 jobs a month and one person.
Three things end it. A second van, because you can no longer see the work without ringing someone. After-hours volume, because that is where unbilled jobs come from. Or a backflow and maintenance book past roughly 30 devices, because a spreadsheet with 30 anniversary dates will fail silently and you will find out when the council does. Short of those, spend the money on stock instead. If the pinch is only the invoicing end, what automating invoicing costs covers the cheaper fixes first.
How to choose in a fortnight
Split last month into two counts: reactive call-outs, and scheduled or contract work. If reactive is the bigger half, trial ServiceM8 and Fergus. If scheduled maintenance and new-build subcontract work is bigger, trial Fergus and simPRO, and read the builders' post for the progress-claim side of head contractor work. Then put a real fortnight of jobs through one of them, gas certificates and all, and compare against the four-way roundup before you commit. If the answer still is not obvious, book a free 30-minute call and talk it through.