The vanity is out. Corroded fittings continue beyond the connection named in the quote. A plumber variation process tells the crew to stop at that boundary, make the system safe and get the extra work approved before cutting further.
Hidden plumbing work is not an open instruction to replace whatever appears. Start with the accepted quote. Record what you found. Decide whether it is included work, an estimating miss or a genuine variation.
The plumber variation process starts with a site hold point
A hold point stops the affected work without stopping the whole job. The crew can protect the site, complete unrelated quoted tasks and wait for a decision.
Use the same plumber variation process whenever concealed pipework changes the job:
- Stop at the quoted boundary.
- Make the system and work area safe.
- Record the visible condition.
- Compare it with the accepted scope.
- Define any investigation or changed repair.
- Price the complete changed task.
- Get approval from the authorised person.
- Update the work order and release the hold.
The plumber variation process only works when the order stays fixed. You cannot price work that has not been defined. You should not start permanent extra work that has not been approved.
Stop at the boundary in the accepted quote
Open the accepted quote or contract. Find the fixture, connection, pipe run, route, access point or test that marks the edge of your work.
A vanity may be removed and corroded fittings may appear beyond the quoted connection point. Excavation may expose a footing across the proposed pipe route. A service test may reveal a separate leak outside the repair boundary.
Mark where your quoted work ends. Do not remove more pipe or open more of the building just to see how bad it might be. That can destroy evidence and commit the customer to work they have not approved.
Make safe without starting the permanent repair
Control the immediate condition. Isolate the service if needed. Drain the affected line, cap an opening, protect exposed pipework or restrict access to the area.
Record the action and the current status. State whether the service is isolated, partly available or returned to service. A make-safe action controls the immediate risk. It does not define or approve the permanent repair.
Other quoted work can continue when it does not cover the evidence, block an inspection or lock the job into a new route. Tell the crew exactly what remains released and what stays on hold.
Tell the customer what has stopped
Send a short notice while the condition is still visible. State what was found, where the accepted scope stopped, what was made safe and which work is paused.
Do not promise a repair price during the first conversation. Tell the customer whether you need approval for an investigation, a changed repair or both.
Record the concealed condition before disturbing it
Build a record that another person can understand without standing beside the opening. Photographs alone are not enough. Notes alone are easy to dispute.
Take a wide photograph showing the room, excavation or fixture location. Then take close photographs of the pipe, fitting, joint, damage, obstruction and surrounding finishes. Add a scale or measurement where size and distance affect the proposed work.
Log these details:
- Customer, site and job reference
- Date, time and crew member
- Exact location of the discovery
- Boundary of the accepted scope
- Visible pipe material and connection type
- Direction and measured extent of exposed pipework
- Test performed and the observed result
- Immediate make-safe action
- Work stopped or left incomplete
- Person notified
Photograph the condition before cutting out the exposed section. If an urgent make-safe action cannot wait, record the condition first where it is safe to do so, then record what was removed.
Write facts about the exposed section
Say what you can see. For example: corrosion is visible beyond the quoted connection, water appeared at a separate joint during testing, or a concealed footing blocks the quoted route.
Do not write that the whole pipe run has failed when the rest remains behind tiles, cabinetry or a lined wall. State that the remaining condition is concealed and untested.
That distinction matters. The visible section may support a defined investigation. It may not support a fixed price for replacing an unknown run.
Decide whether the discovery is actually extra work
The accepted quote or contract is the starting point. Compare the discovery with what you promised, not with what the crew expected the job to involve.
Read the scope, assumptions and exclusions. Check:
- The fixture or service included
- The start and end points of the pipe run
- The named connection point
- Access included in the price
- Isolation and testing included
- Removal and disposal included
- Wall, floor, cabinet, trench or ceiling work included
- Restoration work included
- Exclusions for concealed or adjoining pipework
If the accepted scope already includes the task, complete it under the original job. Do not relabel included work as a variation because it takes longer than expected.
Separate a concealed condition from an estimating miss
Ask what was reasonably visible when you inspected and quoted. Then ask whether the extra task is required to deliver the result already promised.
Treat an omitted task as an estimating miss when it was part of the promised result and could reasonably have been identified before quoting. Record the reason. Do not make the customer carry a missed allowance by changing the description after work starts.
A concealed condition may support a variation when it sits outside the agreed boundary or changes the buildable route. The quote still controls the decision. The fact that the crew did not expect something does not make it extra by itself.
Keep other causes separate. Label a customer-requested addition as a requested addition. Label damage caused by another trade as damage by others. Clear cause codes help the office see why plumbing scope changes keep happening.
Choose the revised plumbing scope before pricing it
Write the changed task from a physical start point to a physical end point. Name the route, access, pipework, fittings, valves, supports, removal, testing, cleanup and return work.
Avoid instructions such as “replace bad pipe as needed”. The customer cannot approve that boundary. The crew cannot tell when it is complete.
Define every physical boundary
State where the changed work starts and ends. Name what remains untouched. If the repair ends at the next sound and testable connection, say how that connection will be identified and tested.
Name who opens and restores walls, ceilings, tiles, floors, cabinetry and trenches. A plumbing variation should not hide builder, tiler or cabinet work under a general cleanup line.
State what happens to removed material. Include protection, disposal and reinstatement only where your business is doing that work.
Split investigation from repair when the pipe remains hidden
When the full condition cannot be seen, define an investigation as its own scope. State the opening, isolation, testing or inspection work included. Set a clear stopping point.
The investigation should produce a decision. That might be a repair scope, an alternative route or confirmation that the original work can continue.
Do not bundle an uncertain investigation and an unknown permanent repair into one fixed description. Price the part you can define. Hold the rest until the evidence exists.
Check the contract and regulator before promising a restart
Identify the job location and contract type before pricing the changed work. Open the accepted contract and check which terms control variations on that job.
Confirm the correct official body for each question at that site. Ask the state or territory licensing regulator about the licence class and regulated contract requirements. Ask the permit or inspection authority about permits, inspections and compliance certificates. Do not assume one body controls every question.
Ask the official regulator whether the changed work needs a prescribed written variation, signatures, notice timing or another approval step. Use any form and approval method required by the accepted contract or regulator.
Send workplace safety questions to the state or territory WHS regulator. That includes questions about isolation, excavation, site openings, access and work-area controls. Do not use a licensing body as the safety adviser.
Record every required inspection, notification and compliance document as a hold point in the work order. Confirm with the relevant authority whether each hold point falls before work starts, during the work, before pipework is covered or at completion.
For GST questions, check the Australian Taxation Office (opens in a new tab) and show GST the same way on the variation and invoice.
Price the complete changed task
Price the chosen scope. Not the urgency. Not the amount you think the customer will accept.
Use this costing worksheet before you apply markup:
Labour cost: [labour quantity] × [business labour cost] = [labour cost] Material cost: [material quantities] × [supplier cost] = [material cost] Equipment cost: [cost] Subcontractor cost: [cost] Disposal cost: [cost] Return-visit cost: [cost] Direct cost total: [total] Overhead treatment: [your normal method] Markup applied once: [amount] Variation selling price: [amount] GST shown: [included or added under your normal document setup]
Labour can include isolation, investigation, access, removal, installation, testing, cleanup and required return visits. Count the complete task, not just the time spent fitting the new pipe.
Materials can include pipe, fittings, valves, supports, protection and disposal items. Add equipment used specifically for the changed work. Add subcontractor costs where another trade handles access or restoration.
Use your own labour cost, supplier cost and overhead method. The job pricing framework explains how to move from scope and cost to a selling price without supplying a rate card.
Apply overhead and markup once
Choose how your business recovers overhead. Include it in the cost base or recover it through your markup method. Do not add the same overhead twice.
Markup is what you add to cost to form the selling price. Margin is the profit left as a share of that selling price. They are not interchangeable. Use the markup and margin guide when checking the calculation.
Keep unknown pipework outside a fixed repair price. If more access is needed before the repair can be scoped, sell the defined investigation first. Guessing the best case only pushes the argument to the final invoice.
Write a variation the crew can build from
The variation should connect the discovery record, revised scope, price effect, timing effect and approver. Give it its own reference and carry that reference through the work order, supplier costs and invoice.
Use this internal variation worksheet to collect the job facts. If the accepted contract or relevant official regulator requires a particular form, timing or approval method, use that requirement instead.
INTERNAL PLUMBING VARIATION WORKSHEET Customer: [name] Site: [address] Job reference: [job number] Original quote or contract: [reference] Variation reference: [reference] Date discovered: [date] Discovered by: [name] Original scope boundary: [fixture, connection, pipe run, route, access, testing and restoration boundary] Condition discovered: [location, visible facts, measurements and test results] Immediate make-safe work: [action taken and current service status] Revised plumbing scope: [start point, end point, route, access, pipework, fittings, removal, testing and cleanup] Work by others: [opening, restoration, cabinetry, trenching, finishes or none] Exclusions and remaining unknowns: [work not included and conditions still concealed] Price effect: [added or reduced amount and whether it includes GST] Timing effect: [changed sequence, return visit, inspection or other effect] Approval status: [approved / declined / pending] Authorised approver: [name and role] Approval record: [method permitted for this job] Approval date: [date] Crew restart instruction: [approved work, boundaries and remaining hold points]
Get approval from the authorised person
The person standing beside the opening may not be allowed to approve extra work. Identify the owner, builder, strata representative, facilities manager or other authorised person under the job arrangement.
For managed sites, name who can approve before the first call-out. The process used for controlling commercial plumbing maintenance work can help you record the approver and purchase-order check before a problem appears.
Use approved, declined or pending. “Discussed on site” is not extra pipework approval. Record who approved the changed scope, the amount, the timing effect and the approval date.
If approval remains pending, keep the affected work held. If it is declined, record whether the system was isolated, made safe, returned to service or left incomplete. Do not delete a declined variation from the job record.
Oak Street worked example: keep the variation visible
The house example is an electrical job, but the document control works the same way for plumbing.
R. Chen’s job at 14 Oak Street covered a bathroom exhaust fan and four LED downlights. Quote Q-1847 totalled 1,105 sample currency units. The ceiling was lined and the quote excluded chasing.
Extra cable and chasing were approved on site as a 160 variation. Invoice INV-1847 was therefore 1,265.
Job cost 850 and profit 255 are measured against the original quote of 1,105. The calculation is 1,105 − 850 = 255. Margin was 255 ÷ 1,105 ≈ 23%, while markup was 255 ÷ 850 = 30%.
The costs of the 160 variation are unknown. Do not combine the job cost of 850 with the 1,265 invoice. Do not calculate profit from the invoice total. These figures demonstrate document control and calculations, not trade rates or target margins.
Release the hold and carry the change through the job
Put the approved variation scope onto the crew work order. Include the physical boundaries, access responsibility, test, exclusions and any remaining hold points. A price approval without a buildable instruction leaves the crew guessing.
Assign actual labour, materials, equipment and subcontractor costs to the variation reference. Keep estimated cost and actual cost separate. The same discipline is shown in this cross-trade guide to tracking labour, materials and profit by job.
Show the approved variation separately on the invoice. Use the same reference and description, and show GST the same way the customer approved it. Do not replace the record with a vague line such as “extra works”.
Yes Foreman can carry an approved variation onto the work order, invoice and job-cost record. That follows the plumber variation process after approval; it does not replace the site evidence or the authorised decision.
Add a concealed-condition hold point and an authorised-approver field to the next plumbing quote you send. Give the crew the same instruction before they open the next wall.