Intro

On most jobs, plumbing work makes or breaks the handover. It’s the bit clients notice first when taps drip, drains gurgle, or water runs cold. This guide shows you how to plan, price, and deliver plumbing work that passes tests and avoids call-backs. We’ll cover first fix, second fix, testing, paperwork, and safety. Use it as a checklist on site. Keep it simple. Do it once. Do it right.

Quick Answer

Plumbing work comes down to planning, correct pipe sizing, clean routing, solid testing, and clear handover. Aim for proper falls on wastes, tight pressure tests, and safe hot water temperatures. Finish with photos, user notes, and clean paperwork to reduce disputes and call-backs.

Table of Contents

• Plan Plumbing Work Right
• First Fix: Pipe Sizing And Routing
• Second Fix: Fixtures And Commissioning
• Testing And Handover For Plumbing Work
• Pricing Plumbing Work, Proposals, And Paperwork
• Safety, Compliance, And Common Mistakes
• Questions And Answers

Key Takeaways

• Plan scope, routes, and isolation before cutting. Saves 1–2 hours.
• Keep waste falls around 18–22 mm per metre for quiet drains.
• Pressure test at 1.5× expected pressure for 30 minutes.
• Set hot water around 50–60°C; use TMVs to deliver 45–48°C at outlets.
• Hand over with photos, valve labels, and a simple user sheet.

Plan Plumbing Work Right

Clear planning saves time and avoids rework.

1. Confirm Scope

• List every outlet: 1 basin, 1 WC, 1 shower, 1 bath, 1 kitchen sink.
• Note special items like a combi, unvented cylinder, or softener.
• Mark isolation valves for each area or fixture.

2. Map Routes

• Sketch hot, cold, and waste routes on the plan.
• Plan straight runs with minimal joints. Avoid tight bends behind tiles.
• Choose fixings and fire-stopping for each wall type.

3. Choose Materials And Sizes

• Domestic copper/PEX commonly at 15 mm and 22 mm. Larger feeds may run 28–32 mm for cylinders or manifolds.
• Use a manifold if many outlets are far apart. It can cut dead legs and boosts flow.

4. Check Codes And Permits

• Follow local water and building regs. Unvented cylinders need competency and certification.
• Allow for access panels and sealing around penetrations.

Tip: If you’re also looking to streamline professional proposals, our guide on “professional proposals” pairs well with this planning step.

First Fix: Pipe Sizing And Routing

First fix is about clean layout and strong support.

1. Pipe Sizing Basics

• Keep mains cold to the combi or cylinder at 22 mm when runs are long. Step down to 15 mm near outlets.
• Balance hot and cold sizes to avoid pressure drops when two taps run.

2. Waste Pipes And Falls

• Aim for a fall of 18–22 mm per metre on 32–40 mm wastes. Too flat invites blockages. Too steep can lose water seals.
• Keep trap water seals at about 50 mm to stop smells.

3. Supports And Protection

• Support small-bore copper every 0.6–1.2 m. PEX often needs closer clips; follow the manufacturer.
• Protect pipes through studs with grommets. Use nail plates where needed.

4. Penetrations And Zoning

• Drill level, use pipe collars later for a clean finish.
• Label hot, cold, and returns with tape or marker. You’ll thank yourself at second fix.

5. Timeframe

• A standard bathroom first fix often takes 1 day. Larger layouts can run 1–2 days depending on structure.

Common mistake: Mixing push-fit brands. Don’t. Stick to one system per run.

Second Fix: Fixtures And Commissioning

Second fix is where clients judge your work. Keep it tidy.

1. Set-Out And Sealing

• Level and square everything. Use a laser for rows of taps and shower mixers.
• Use quality silicone. Smooth with a tool. Allow 24 hours cure before flood testing a shower tray.

2. Valves And TMVs

• Fit isolation valves on every outlet you can reach. It saves hours later.
• Use thermostatic mixing valves to deliver about 45–48°C at basins and showers.

3. Hot Water And Recirc

• Set cylinder thermostats around 50–60°C. Follow the manufacturer and local guidance.
• If you have a secondary return, insulate it well and use timers to save energy.

4. Final Connections

• Flush pipework before connecting taps. Protect cartridges from debris.
• Tighten by hand first, then spanner. Don’t over-tighten flexible tails.

5. Timeframe

• A small bathroom second fix is often half a day to a day. Kitchens vary with appliances.

Testing And Handover For Plumbing Work

Testing proves your plumbing work before the client finds faults.

How To Pressure Test A Domestic System

1. Cap open ends and close all outlets.
2. Connect a pressure pump and gauge to a low point.
3. Pressurise to around 1.5× expected working pressure.
4. Hold for 30 minutes. Watch the gauge. No drop means good.
5. Check all joints with tissue or leak spray. Fix any weeps.

Note: Always follow the pipe manufacturer’s method. Some systems prefer air; others prefer water.

Drain Tests

• Flood test trays and baths for at least 10–15 minutes.
• Fill basins and sinks to the overflow. Check for drips at traps and wastes.

Commissioning Checklist

• Measure outlet temperatures: aim for 45–48°C at TMV-controlled outlets.
• Balance flows where mixers are weak.
• Label isolators and the main stopcock.

Handover Pack

• Photos of valves and routes.
• Simple user sheet: where to turn off, how to clean filters, service dates.
• Record test pressures, times, and any serial numbers.

This pairs well with understanding “project timelines” so you book tests before tiling and decoration.

Pricing Plumbing Work, Proposals, And Paperwork

Good pricing protects your margin and sets clear client expectations.

1. Build A Simple Take-Off

• Count outlets and metres of pipe. Include 15 mm, 22 mm, and any 28–32 mm sections.
• Add fittings, valves, traps, and clips. Don’t forget waste traps and silicone.

2. Labour And Time

• First fix a standard bathroom: often 1 day.
• Second fix and testing: often 0.5–1 day.
• Add time for awkward access or older buildings.

3. Clear Scope In Proposals

• List what’s included: fixtures, valves, TMVs, testing, and making-good.
• List exclusions: tile repairs, electrical works, and hidden defects.

4. Reduce Admin Time

• Use solutions like Donizo to capture site notes with voice, create a clean proposal, and send a branded PDF. E‑signatures cut delays, and accepted proposals convert to invoices in one click.

5. Variations

• Price changes before starting extra work. Put it in writing. It prevents arguments.

If you want to sharpen your numbers, check resources on “pricing strategies” and “invoice templates”. They fit neatly with this section.

Safety, Compliance, And Common Mistakes

Keep people safe and stay compliant. It also protects your business.

1. Hot Water Safety

• Use TMVs in homes with children or older people. Target 45–48°C at outlets.
• Keep stored hot water around 50–60°C as per manufacturer guidance.

2. Backflow And Contamination

• Fit double check valves where required. Keep hose bibbs protected.

3. Fire-Stopping And Seals

• Seal all penetrations with approved products. Photograph before closing walls.

4. Common Mistakes To Avoid

• No isolation valves. Add them.
• Over-tightening plastic fittings. Tight but not crushed.
• Zero slack on tails. Leave a touch for movement.
• Poor waste fall. Hold 18–22 mm per metre where you can.

5. Documentation

• Keep model numbers, serials, and manuals. It saves repeat visits later.

Questions And Answers

How long does a standard bathroom’s plumbing work take?

In general, first fix takes about 1 day and second fix another 0.5–1 day. Add time for testing, flood checks, and any remedial work. Older buildings or tricky layouts can add a day or more.

What pipe sizes should I use in a small house?

Commonly, run mains and hot feeds in 22 mm for longer runs, then step down to 15 mm near outlets. For single bathrooms close to the source, 15 mm may be fine. Keep wastes at 32–40 mm with proper falls.

What is a good fall for waste pipes?

Aim for about 18–22 mm per metre. Too flat risks blockages. Too steep can pull traps and cause smells. Keep a 50 mm water seal in traps.

How should I pressure test new pipework?

Cap all ends, connect a gauge, and pressurise to about 1.5× expected pressure. Hold for 30 minutes with no drop. Check every joint. Follow the manufacturer’s method and local guidance.

What should I include in my plumbing work handover?

Include photos of valves, a simple user sheet, test records, temperatures at outlets, and service notes. Label the main stopcock and any isolation valves. This reduces call-backs and keeps clients confident.

Conclusion

Delivering solid plumbing work is about planning routes, sizing pipes right, setting safe temperatures, and proving it all with clean tests. Put everything in writing, label valves, and hand over photos. Next steps: 1) Build a repeatable checklist from this guide, 2) Standardise your testing and handover pack, 3) Use tools like Donizo to turn site notes into signed proposals and quick invoices. Do the basics well, and the jobs get easier, cleaner, and more profitable.