A client calls about a leaking hot water system. You quote $180 call-out plus $110 an hour, they say "just come have a look." You get there, the unit is 14 years old and corroding at the base, and now you are having a conversation about a $2,200 replacement standing in their laundry with wet socks. That conversation goes a lot better if you know exactly how you price both halves of that job before you walk in the door.
Plumbing sits in an odd spot compared to other trades because so much of the work is genuinely unpredictable until you can see it. A tiler can measure a room and price it accurately from a tape measure. A plumber often cannot know what is behind a wall until the wall is open. That uncertainty is exactly why plumbing quotes go wrong more often than most - and exactly why getting the structure right matters more here than almost anywhere else.
The short answer
Use call-out plus hourly pricing for fault finding and anything with unknown scope. Use fixed price for jobs you can fully specify upfront - hot water replacements, bathroom renovations, defined install work. Mark up materials 20 to 40% depending on the item. Build a conditional allowance into fixed-price quotes for hidden pipework, and get sign-off on any variation before continuing.
1. Call-out and hourly - when it actually makes sense
A call-out fee plus an hourly rate is the right model when you genuinely do not know what the job involves until you are standing in front of it. Fault finding is the clearest example: a client says "there's a leak somewhere near the kitchen" and you have no idea if that means a $90 tap washer or three hours tracing a pipe through a wall cavity.
A typical structure:
- Call-out fee: $80-$150, covers travel and the first diagnostic look. Non-refundable, applied against the job if they proceed.
- Hourly rate: $95-$150 depending on region and whether it's after hours.
- After-hours or emergency multiplier: commonly 1.5x to 2x standard rate for evenings, weekends, and public holidays.
Say it out loud on the phone before you drive out. "There's an $110 call-out fee that covers me coming to have a look, and then it's $120 an hour after that if you want me to fix it." That sentence takes eight seconds and prevents almost every argument about the invoice later.
2. Fixed price - when the scope is actually known
If you can walk through exactly what the job involves before you start - a hot water system swap, installing a new bathroom, connecting a dishwasher, replacing a toilet - fixed price is usually the better move. Clients trust a number they can plan around, and a well-priced fixed quote protects your margin better than hourly does on a job you can do efficiently.
A worked example. Replacing a 250L electric hot water system, straightforward access, like-for-like swap:
- Unit (trade price $1,450, marked up 25%): $1,812.50
- Fittings, isolation valve, expansion vessel: $180
- Labour, 3 hours: $360
- Disposal of old unit: $60
- Subtotal: $2,412.50
- GST: $241.25
- Total: $2,653.75
Written out like that, the client sees exactly where their money goes. A single number with no breakdown invites a "why is this so expensive" conversation. An itemised one usually does not.
3. Materials markup - what's actually reasonable
Most plumbers mark up materials between 20% and 40% on trade price. The variation depends on the item:
Small fittings and parts - washers, valves, connectors - often sit at the higher end, 30-40%, because the time cost of sourcing, holding stock, and the inevitable second trip to the supplier is baked into that margin even though it does not show up as its own line item.
Big-ticket items like hot water systems often sit lower, 20-25%, because a 40% markup on a $2,000 unit looks steep to a client who can search the retail price on their phone while you are still in the driveway. A lower percentage on a big number still produces a healthy dollar figure.
Whatever percentage you land on, be consistent. Pricing materials by feel job to job is how margin quietly leaks out of a business without anyone noticing until the BAS numbers look worse than expected.
4. The bathroom renovation - a mixed pricing job
Bathroom renos are a useful example because they combine both approaches. You can fix-price the parts you can see and specify - moving a toilet, roughing in for a new vanity, running new supply lines to a known layout. But you cannot always be certain what condition the existing pipework is in until it is exposed.
Handle it like this: quote the rough-in and fit-off as a fixed price based on the agreed layout, and add a stated allowance - say $400 - for addressing any unexpected pipe condition or access issue, with a clear note that anything beyond that allowance will be quoted as a variation before proceeding. This gives the client a number to plan around while protecting you from absorbing a genuine surprise, like finding galvanised pipe that should have been replaced two owners ago.
5. Emergency callouts - price for the disruption, not just the time
An emergency callout at 11pm on a Sunday is not the same job as the same task at 10am on a Tuesday, even if the actual repair takes identical time. You are giving up your evening, your family time, and your ability to plan the next day.
Price accordingly. A 1.5x to 2x multiplier on your standard hourly rate for after-hours and emergency work is standard across the trade, and clients calling at 11pm with a burst pipe are rarely price-shopping. State the emergency rate clearly when they call, before you get in the van - not as a surprise on the invoice the next morning.
6. What to put in the quote to protect yourself on hidden pipework
This is the single most common source of plumbing disputes: the client expected one price, the wall came off, and the pipe run was nowhere near where anyone expected. A few lines in your quote prevent most of this:
"This quote is based on visible access and standard pipe location as assessed at time of quoting. If pipework is found to differ from expected location, condition, or requires additional access to reach (including but not limited to tile removal, ceiling access, or concrete cutting), this will be identified, photographed, and quoted as a variation before work proceeds."
That single paragraph does three things: sets the client's expectation honestly, gives you a documented process to follow if something unexpected turns up, and removes any ambiguity about who agreed to what if the final invoice differs from the original quote. Photograph everything you find that changes the scope, and do not proceed on the variation until the client has actually agreed to it - a text message confirmation is enough, but get something in writing.
7. Standard exclusions worth listing every time
Spell these out even when they feel obvious, because the client's understanding of "plumbing job" and yours are not always the same thing:
- Tiling and waterproofing, unless specifically included in your scope.
- Electrical work needed to relocate a hot water system or connect an appliance.
- Making good to walls, floors, or ceilings after pipe access.
- Council permits or approvals, if the job requires them.
- Asbestos testing or removal if the property is pre-1990 and the work disturbs a wall or ceiling - see the guide on asbestos awareness for tradies for what triggers this and what to do about it.
8. Putting the quote together
A plumbing quote that protects both you and the client includes:
- Clear identification of which pricing model applies - call-out/hourly or fixed price.
- Materials itemised separately from labour, with markup baked in but visible as a total.
- A stated allowance for hidden conditions on fixed-price jobs, with a variation process explained.
- Exclusions listed specifically.
- Quote validity period - 30 days, given material prices move.
The Proposal and Quote Builder in Smart Tools handles this structure so you are not rebuilding the same document from scratch every time. For the underlying question of what your hourly rate should actually be, see how to set your labour rate as a tradie, and if a variation does come up mid-job, the guide on how to write a variation covers exactly how to handle it without it becoming an argument.
Frequently asked questions
Should plumbers charge hourly or a fixed price?
Depends on how much you can see before starting. Fault finding and anything with genuinely unknown scope suits call-out plus hourly. A hot water replacement, a bathroom reno with an agreed layout, or any job you can fully specify in advance suits fixed price. Fixed price builds trust on straightforward jobs. Hourly protects you on the ones where nobody knows what's really going on until the wall comes off.
What markup should plumbers charge on materials?
Typically 20% to 40% on trade price. Small fittings and parts often sit higher, 30-40%, because sourcing and stock-holding time is baked in. Big-ticket items like hot water systems often sit lower, 20-25%, because a high percentage on an already expensive item looks steep to a client who can check the retail price themselves.
How do I quote for hidden pipework I can't see before starting?
State in the quote that pricing is based on visible access and standard pipe location, and that anything found to differ once work begins will be photographed and quoted as a variation before proceeding. This protects you from absorbing a genuine surprise and protects the client from an unexplained number on the final invoice.
What should be excluded from a plumbing quote by default?
Tiling and waterproofing, electrical work to relocate or connect appliances, making good to walls or floors after pipe access, council permits if required, and asbestos testing or removal on pre-1990 properties where the work disturbs a wall or ceiling. List these even when they seem obvious - clients often assume they're included.