In Part 3, we explored the must-know plumbing regulations that every owner builder should understand before construction begins.
Now, in this final instalment of our 4-part plumbing series, it’s all about working with your plumber. Nathan shares the key things to look for when hiring, how to read between the lines of a quote, and what plumbing should actually cost.
Let’s wrap things up with practical insights that could save you time, money and headaches!
How to Choose the Right Plumber
Finding someone who’s qualified and trustworthy is crucial. According to Nathan:
“The number one thing? Make sure they’re licensed. And don’t be afraid to ask for proof of insurance too.”
Here are Nathan’s key recommendations:
✅ Ask for their plumbing licence and check it with your state authority
✅ Confirm public liability insurance is current
✅ Check reviews on Google or Facebook
✅ Visit your local plumbing supplier and ask for recommendations
🔧 Pro tip: If a plumber is unwilling to provide proof of licence or insurance, consider it a red flag.
Understand What You’re Being Quoted For
Not all quotes are created equal. Some plumbers provide an all-inclusive quote; others break it into stages like drainage, rough-in, and fit-off.
“I always tell people to make sure everything you discussed is written into the quote. If something’s missing, ask why.”
Watch for these common traps:
❌ Vague or incomplete quotes
❌ No mention of complex items like stone baths (which may need a crane)
❌ Unexpected ‘variations’ added later
🔧 Pro tip: Review multiple quotes side-by-side and compare what's included.
Is a Quote Legally Binding?
Yes! A written quote from a plumber can act as a basic contract.
“For big jobs like new builds, we need to lodge a formal contract with the QBCC here in Queensland. But for smaller renovations, the quote often acts as the agreement.”
🔧 Pro tip: If your job is over $3,000, ask your plumber whether it requires a formal building contract.
What Does Plumbing Actually Cost?
Prices vary based on the type of job, but Nathan gives these ballpark figures:
🛁 Basic bathroom renovation (no fixture movement): $3,000
🛠️ Renovation needing new drainage/slab cutting: $4,000–$5,000
🏡 New build plumbing: $10,000–$25,000 (depending on size and complexity)
“Renovations are harder because you don’t know what’s behind the walls. New builds are more straightforward.”
🔧 Pro tip: Always budget a buffer. Surprises behind walls can add to your plumbing bill.
Build a Good Working Relationship
Nathan says communication is key and owner builders should feel comfortable asking questions.
“I always walk customers through the job after rough-in. You should never be afraid to ask what’s been done and why.”
🔧 Pro tip: Before walls go up, ask your plumber to walk you through the work. It’s easier to fix things now than later.
Wrapping it Up
This wraps up our 4-part series with Nathan Rich from KNR Mechanical Plumbing. From pre-planning to hiring, we’ve covered the essentials to help you tackle your build with confidence.
Missed a part? Catch up here:
Part 3: Understanding Plumbing Regulations & Compliance
Part 2: 5 Common Plumbing Mistakes (and How to Avoid Them)
Part 1: Plumbing Design Tips for Owner Builders
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About Nathan – KNR Mechanical Plumbing
Nathan runs KNR Mechanical Plumbing on the Sunshine Coast and has built a solid reputation for being friendly, down-to-earth, and great at what he does. With loads of experience in residential builds and renos, Nathan takes pride in doing the job right. No shortcuts, just honest advice and quality work.
If you’re after a plumber who actually cares about your build, he’s your guy.
