Running a Hot Water Plumbing Business in Australia
Friday afternoon, a family of four, no hot water. The client needs it fixed today. You quote the job over the phone based on what they describe — a standard 250L gas storage unit on the side of the house. You load the van, drive to the job, and discover it's a 315L unit with an expansion valve, tempering valve, and isolation that needs replacing too. The second truck run is already happening in your head. This is the hot water business.
What a hot water business looks like
What actually kills the margin in hot water work
The second truck run — the margin killer
The second truck run on a hot water job costs you more than time. It costs you credibility with the client, a delay on their critical situation, and typically the margin on the entire job once you factor in the fuel, the wasted time, and the cost of the incorrect parts that couldn't be returned.
It happens almost every time because the unit spec wasn't confirmed before loading the van. The client said "it's a Rheem." There are dozens of Rheem models. What size? What fuel? What connections? Roof access or wall mount? Is there an existing expansion vessel?
Build a pre-dispatch checklist into every hot water job:
- Brand and model number (from the label on the existing unit)
- Capacity in litres
- Fuel type (natural gas / LPG / electric / solar)
- Connection type (copper push-fit, compression, or threaded)
- Tempering valve present? Age?
- Expansion control valve?
- Access constraints (roof, under-house, garage, outdoor wall mount)
- Disposal: is the old unit removable without a crane or second person?
Send the checklist as a text message to the client before dispatch. Ask them to find the model sticker on the unit and send a photo. 60 seconds of information gathering prevents the second truck run entirely.
STC rebate confusion — who owes what
On solar hot water replacements, the STC rebate is a genuine financial benefit to the client — typically $400–$800 off the cost of the install. But the way most operators handle it creates confusion. The client has been told there's a rebate. They're not sure if they owe you the full price or the rebated price. They may try to stall payment "until the rebate comes through."
The clean approach: quote the full job price, show the STC rebate as a line item discount on the invoice, collect the discounted amount on completion, claim the STCs yourself. The client pays you the net figure on the day. Done. No ambiguity about what they owe or when.
Disposal — the cost that's not in the quote
Old hot water units are heavy, often awkward, and increasingly difficult to dispose of. Many tip facilities won't accept certain types without a fee. Some won't accept them at all without draining certification. If disposal isn't a specific line item in your quote, it either gets absorbed into your margin or creates a dispute at invoice time. Always quote disposal as a separate line item with a stated fee.
Where the money is leaking
| Stage | What You Need | What's Actually Happening |
|---|---|---|
| Quoting | Pre-dispatch checklist confirms unit spec, connections, access, and disposal before loading the van. Quote includes disposal as a line item. | Unit type assumed from client description. Wrong unit loaded. Second truck run. Disposal not in quote — dispute at invoice. |
| Job Management | Photo of existing unit before removal. Photo of installation complete. Old unit disposal documented (tip docket). Install date recorded for warranty start. | No documentation. Client disputes installation 6 months later. Warranty start date unknown. Tip docket thrown in the bin. |
| Invoicing | Invoice on commissioning — not the next day. STC rebate shown as a line item discount. Disposal fee line item. Unit supply + install + tempering valve + disposal all itemised. | Invoice sent next day. STC rebate handled separately — client confused about what they owe. Disposal not itemised — disputes at payment. |
| Payments | Collect on commissioning day. BNPL option available for large emergency jobs. No "I'll transfer it tonight." | Emergency situation resolved, urgency gone, transfer promised but delayed. Friday afternoon job not followed up until Monday. |
What hot water plumbers actually need
Custom job intake form captures unit spec before dispatch. Photo capture for before/after documentation. Compliance form module for gas certificate. Invoice on commissioning from your phone. Tip docket photo attached to job record.
Compare job management tools →Humm Business or Zip Business allows your clients to pay over time while you receive the full amount immediately. On a $2,500 emergency Friday afternoon job when the client's savings aren't liquid — BNPL is the difference between a completed job and a delayed payment conversation.
Compare payment options →For larger hot water jobs — solar systems, heat pump installs, commercial replacements — a written quote protects you. ServiceM8 and Tradify both allow quote creation from your phone on site. Send it before you leave, get acceptance, then order materials.
Compare quoting tools →Still loading the van based on what the client describes over the phone?
The Strategy Builder identifies the exact gaps in your hot water business workflow — and the tools that fix them.
Build My Free Strategy →Frequently Asked Questions
Build a pre-dispatch checklist into every job: fuel type, capacity, brand and model, connection types, tempering valve status, access constraints, and disposal requirements. Text the checklist to the client before dispatch and ask them to send a photo of the model sticker. 60 seconds of information gathering prevents the most expensive mistake in hot water work.
Quote the full job price, show the STC rebate as a discount line item on the invoice, and collect the net amount on commissioning day. 'Total: $2,400. Less STC rebate: -$600. Amount owing: $1,800.' You claim the STCs. They never touch the rebate paperwork. This eliminates all confusion about what they owe and when.
Add BNPL (Buy Now Pay Later) options to your payment methods — Humm Business or Zip Business allow the client to pay over time while you receive the full amount immediately. A $2,500 emergency replacement on a Friday afternoon is exactly the use case BNPL was built for. Many hot water plumbers find it converts jobs they would otherwise lose to "I need to think about it."