Intro

On most jobs, plumbing work makes or breaks the schedule. One small leak can cost a full day. Poor fall means blockages and call-backs. This guide gives you a simple, field-tested plan for plumbing work. We cover planning, rough-in, testing, and final fix. We also show how to price clearly and handle paperwork without headaches. Follow these steps to keep your plumbing work tight, clean, and on time.

Quick Answer

Plumbing work runs best when you plan the route, size pipes right, and test under pressure before closing walls. Keep waste falls consistent, support pipes often, and commission fixtures carefully. Document changes fast and invoice cleanly to avoid disputes and delays.

Table of Contents

• Planning The Plumbing Work (#planning-the-plumbing-work)
• Rough-In: Sizing, Fall, And Fixings (#rough-in-sizing-fall-and-fixings)
• Pressure And Leak Testing: Step-By-Step (#pressure-and-leak-testing-step-by-step)
• First Fix To Final Fix (#first-fix-to-final-fix)
• Pricing And Paperwork For Plumbing Work (#pricing-and-paperwork-for-plumbing-work)
• Quality, Safety, And Common Mistakes (#quality-safety-and-common-mistakes)
• FAQ (#faq)
• Conclusion (#conclusion)

Key Takeaways

• Test at 1.5× working pressure and hold for 30 minutes.
• Aim for 1:40 to 1:60 fall on waste lines (about 2.5%–1.7%).
• Support most pipes every 1.0–1.5 metres to stop sagging.
• Typical small flat rough-in: 1–2 days; whole house: 3–5 days.
• Set hot water storage around 55–60°C; temper outlet to 41–43°C.

Planning The Plumbing Work

Good plumbing work starts before tools come out. A clear plan avoids rework.

• Mark every fixture on drawings and on walls/floors. Use centre lines.
• Walk the job with the GC and spark. Agree routes and heights.
• Check the water main size and pressure. In general, 3–5 bar is common on mains. Note if a booster is needed.
• Confirm drain exit point and invert level. Make sure your internal falls will hit it.
• Choose pipe types early. Don’t mix push-fit and solder at random. Keep it consistent per zone.
• List valves, traps, and isolation points. One per fixture is best practice.

Action you can take today:

1. Print a one-page scope for plumbing work. Include fixtures, pipe types, and test method.
2. Create a simple route sketch per floor. Mark pipe sizes and falls.
3. Book inspection windows into the programme: rough-in check, pressure test, and final sign-off.

Internal link opportunities:

• If you’re also looking to streamline professional proposals, our guide covers the must-haves.
• This pairs well with understanding project timelines and milestone planning.

Rough-In: Sizing, Fall, And Fixings

Most problems in plumbing work start at rough-in. Keep it tight here.

Pipe sizing basics

• Cold and hot feeds to basins: commonly 15 mm pipes.
• Baths and showers often need 22 mm feeds if pressure is low.
• Keep runs short; reduce elbows. Every bend costs flow.

Waste pipe fall

• Aim for a fall of 1:40 to 1:60 (about 25 mm per metre to 17 mm per metre).
• Too flat = blockages. Too steep = water outruns solids.
• Keep long runs vented as required. Avoid trap siphonage.

Fixings and spacing

• Support copper or plastic pipes every 1.0–1.5 metres on horizontals.
• Verticals can go wider, but clamp near changes of direction.
• Sleeve pipes through walls and floors. Leave 10–20 mm clearance where needed.
• Keep water lines at least 100 mm clear of electrics where possible.

Heights and set-outs (check local code/manufacturer)

• Basin top: commonly 850–900 mm from finished floor.
• Shower outlets: often 1100–1200 mm; heads 2000–2100 mm.
• WC clear space: aim for 750–800 mm width and 600–700 mm front clearance.

Tip: Before boarding, take photos with a tape in frame. It saves you 2–3 hours later when someone asks, “Where’s that pipe?”

Internal link opportunity:

• For contractors dealing with change orders, we recommend clear change order language to protect margins.

Pressure And Leak Testing: Step-By-Step

Never skip testing. It’s the cheapest insurance in plumbing work.

1. Cap or plug all outlets securely. Use blanks, not tape makeshifts.
2. Fill the system slowly and bleed air. Air hides leaks.
3. Test pressure: In general, use 1.5× working pressure. If you expect 4 bar in service, test near 6 bar (or follow manufacturer guidance).
4. Stabilise for 10–15 minutes. Temperature changes move the gauge.
5. Hold test for 30 minutes. Record start and finish readings. Allowable drop should be zero on water tests.
6. Walk every metre of pipe. Run a dry cloth over joints. Any damp is a fail.
7. For drainage, do a water test or air test per local rules. Many use a 1.2 m head of water or a low-pressure air test with a manometer. Hold for 5–10 minutes.
8. Sign the test sheet. Get the GC or client rep to countersign.

Keep your test sheets. They close arguments fast months later.

Internal link opportunity:

• This ties into invoice templates that save time when billing for testing and certification.

First Fix To Final Fix

When the walls close, you move into the tidy phase of plumbing work.

First fix checks

• Protect pipe ends. Dust ruins cartridges and valves.
• Insulate hot and recirculation lines. 13 mm insulation is a common minimum for small-bore lines.
• Penetrations: fire-stop to spec. Label zones if required.

Second fix and commissioning

• Fit valves, taps, WCs, and traps. Keep seals clean and un-twisted.
• Flush lines for 2–3 minutes before fitting aerators.
• Balance systems: open nearest rads or outlets first, then the rest.
• Set temperatures: storage around 55–60°C; tempering valves 41–43°C for baths/showers where required.
• Run each fixture for 2 minutes. Check for drips under load and when off (static pressure reveals weeps).

Handover

• Show the client the main stop tap and isolations. Label them.
• Give simple care notes: how to clean, how to reset, and warranty details.

Pricing And Paperwork For Plumbing Work

Clear paperwork keeps your plumbing work profitable and calm.

• Break quotes into labour, materials, and allowances. List exclusions.
• Add a test and commissioning line. Don’t hide it.
• Price variations the same day. Photos plus a short note wins trust.
• Get signatures before extra work. Verbal approvals vanish later.

Tools can help here. With platforms such as Donizo, you can:

• Use Voice to Proposal to capture site notes, then generate a branded proposal fast.
• Send Proposal for e-signature via a client portal, so approvals are clear and binding.
• Convert accepted proposals to invoices in one click, keeping your trail clean.

Internal link opportunities:

• If you’re pricing bigger jobs, see our pricing strategies resource.
• Creating professional proposals becomes much easier with a repeatable template.

Quality, Safety, And Common Mistakes

Quality and safety are part of good plumbing work.

Quick QA checklist

• Correct pipe sizes and consistent falls.
• Supports within 1.0–1.5 metres on horizontals.
• All joints tested and dry after 30-minute hold.
• Isolation valves at every fixture group.
• Photos taken before close-up.

Safety basics

• Hot works: permit, fire watch 60 minutes after soldering.
• Confined spaces: test air, ventilate, and have a spotter.
• Lifting cylinders: use two people or a dolly. Protect your back.
• Lock off power tools and pressure testers when unattended.

Common mistakes to avoid

• Burying untested joints. Always test before boarding.
• Over-tightening plastic fittings. Hand-tight plus a quarter turn is often enough.
• No access to traps or valves. Future you will be grateful for access panels.
• Mixing metals without dielectric breaks. Stop corrosion before it starts.

FAQ

What does plumbing work usually include?

It covers water supply, hot water, waste and vent pipes, fixtures, valves, and testing. On many jobs it also includes commissioning, insulation, and simple handover documents. Gas and heating may be separate trades, depending on the project.

How much fall do I need on waste pipes?

In general, aim for 1:40 to 1:60. That’s roughly 25–17 mm fall per metre. Keep it consistent. Too much fall can be as bad as too little. Always check local code and the pipe manufacturer’s guidance.

When should I pressure test?

Right after rough-in and before any walls or ceilings are closed. Hold a water pressure test for about 30 minutes at roughly 1.5× working pressure, unless the manufacturer states otherwise. Record the readings and get them signed.

How long does rough-in take?

It depends on size and access. A small flat with one bathroom might take 1–2 days for a two-person crew. A larger house with multiple bathrooms can take 3–5 days. Material delivery and clear routes speed it up.

Push-fit or solder: which is better?

Both work when installed right. Push-fit is fast and great for tight spots. Solder is durable and handles heat well. Don’t mix systems randomly. Follow the manufacturer’s tools and insertion depths, and always test.

Conclusion

Strong plumbing work comes from smart planning, clean rough-in, and strict testing. Keep falls steady, support pipes often, and commission with care. Document changes the same day and get clear approvals. If you want faster, clearer paperwork, tools like Donizo help you capture site notes, send proposals for e-signature, and invoice in one flow.

Next steps:

• Map your routes and sizes before cutting a single pipe.
• Pressure-test at 1.5× working pressure and log the results.
• Standardise your proposal and test sheet templates.

Do this, and your jobs will run smoother, finish cleaner, and pay faster.