“How to Install a Toilet the Right Way — Professional Plumber’s Guide (Singapore)”
- SURESH K
- Oct 27
- 5 min read
Installing a toilet might seem like a simple task—but doing it correctly makes all the difference between years of trouble-free performance and constant leaks or odours. Whether you’re renovating a bathroom, replacing an old WC, or setting up a new unit in a commercial property, proper toilet installation ensures hygiene, water efficiency, and comfort.
In this detailed guide, we’ll walk through everything you need to know about toilet installation—from preparation to finishing touches—so you can understand how professionals like Alpha & Omega Trinity Pte Ltd (AOT) handle the job safely and efficiently.
🧰 Step 1: Preparation and Planning
Before touching any tools, proper preparation is key. Here’s what a professional plumber does before starting work:
1. Inspect the Area
Check water supply location: The shut-off valve should be within easy reach and in good condition.
Confirm waste outlet type: Toilets connect to either a floor outlet (S-trap) or wall outlet (P-trap). Choosing the right toilet type ensures a perfect fit.
Examine floor condition: The sub-floor or tiles must be level, dry, and strong enough to support the new toilet.
2. Gather the Right Tools and Materials
A professional plumber always comes prepared. Typical tools include:
Adjustable wrench and screwdrivers
Measuring tape and marker
Putty knife or scraper
Hacksaw (for trimming bolts or pipes)
Toilet flange bolts and nuts
Wax ring or rubber gasket seal
Silicone sealant
Spirit level
Having all tools ready ensures smooth and uninterrupted installation.
🚽 Step 2: Removing the Old Toilet (If Replacing)
If an old toilet is being replaced, safety and cleanliness are important.
Shut off the water supply. Turn the valve clockwise to close it completely.
Flush the toilet to remove as much water as possible. Use a sponge or small container to remove leftover water from the tank and bowl.
Disconnect the water hose from the bottom of the tank.
Unscrew the nuts from the base bolts that secure the toilet to the floor.
Gently lift and remove the old toilet. Rock it slightly to loosen the wax seal.
Clean the flange area—remove the old wax and debris to ensure a perfect seal later.
⚠️ Tip: Always block the drain hole with a rag after removing the toilet to prevent sewer gas from escaping.
🧩 Step 3: Installing the New Toilet Flange (if needed)
The toilet flange is the ring that connects the toilet to the drainpipe.A damaged or corroded flange can cause leaks and instability.
Inspect the existing flange. If it’s cracked, rusted, or loose—replace it.
Position the flange so that the bolt slots align at 3 and 9 o’clock positions.
Secure it firmly to the floor using stainless screws or anchors.
This ensures the toilet will sit level and tight on the floor.
💧 Step 4: Setting the Wax Ring or Seal
A wax ring (or rubber seal) is what keeps sewer gases and water from leaking under the toilet.
Turn the new toilet upside down carefully.
Press the wax ring around the outlet horn of the toilet bowl.
Make sure it’s centred and evenly compressed.
💡 Pro Tip: Many modern toilets now use rubber gasket seals instead of wax. They’re cleaner, reusable, and easier to adjust during installation.
🪛 Step 5: Positioning the Toilet
This is one of the most crucial steps. The toilet must be aligned perfectly over the flange.
Lower the toilet bowl straight down, ensuring the flange bolts go through the holes on the base.
Press down firmly to compress the wax ring.
Wiggle gently side-to-side (not too much!) to seat it securely.
Place washers and nuts on the bolts, and tighten evenly on both sides.
⚠️ Do not overtighten! Over-tightening can crack the ceramic base.
🚿 Step 6: Installing the Tank (for Two-Piece Toilets)
If your toilet has a separate tank and bowl:
Place the rubber gasket on the bottom of the tank outlet.
Set the tank on the bowl, aligning the holes.
Insert the bolts and tighten them evenly and alternately until snug.
Connect the fill valve hose to the tank’s inlet.
✅ Always check that the tank sits level and doesn’t wobble.
💦 Step 7: Connecting the Water Supply
Attach the flexible hose from the shut-off valve to the tank’s inlet thread.
Hand-tighten first, then give a gentle quarter-turn with a wrench.
Slowly open the water valve and let the tank fill up.
Check for leaks at all joints and connections.
💧 If any leaks appear, slightly tighten the fittings—but never force them.
🧼 Step 8: Sealing and Finishing
Once everything is watertight and properly aligned:
Use white silicone sealant around the base of the toilet to prevent water or dirt from seeping underneath.
Trim the flange bolts and cap them with plastic covers.
Install the toilet seat cover according to manufacturer instructions.
🧽 Clean the toilet and floor area thoroughly before testing.
🔄 Step 9: Testing and Adjustment
Flush several times and check for leaks at the base and hose connection.
Make sure the toilet bowl refills correctly and the flush works efficiently.
Confirm that there’s no rocking movement—if it wobbles, add plastic shims and re-seal.
🧰 AOT’s technicians always run multiple tests before leaving the site to guarantee complete functionality.
🧑🔧 Professional Tips from Alpha & Omega Trinity
At Alpha & Omega Trinity Pte Ltd, our plumbing specialists in Singapore follow strict installation and hygiene standards for every project. Here are a few expert insights from our team:
Always choose the correct trap type – Singapore homes typically use S-trap toilets for floor outlets, while condos and newer buildings often use P-trap types.
Check PUB (Public Utilities Board) approval – Toilets sold in Singapore must meet PUB’s water efficiency standards (Water Efficiency Label, WELS).
Never reuse old wax rings – It can cause leaks within days.
Level the toilet – A tilted toilet can lead to stress cracks and poor flushing performance.
Flush test before sealing – This ensures you can adjust the position if needed.
🏢 Why Hire a Professional Plumber?
While DIY installation seems tempting, toilets involve both plumbing and sealing precision. Improper installation can cause:
Leaks that damage tiles or ceilings below
Sewer gas odour due to poor sealing
Loose toilets that shift over time
Inefficient flushing or refilling problems
By hiring licensed professionals like Alpha & Omega Trinity Pte Ltd, you get:
Certified plumbers trained to handle all types of WC installations
High-quality fittings and approved materials
Workmanship warranty and PUB-compliant work
Fast response and transparent pricing
🧾 Maintenance and Aftercare Tips
After installation, proper maintenance extends the life of your toilet.
Avoid harsh cleaners that damage rubber seals and glaze.
Check for leaks at the base every few months.
Tighten seat bolts if they become loose.
Use gentle flush valve cleaners to prevent buildup.
Schedule yearly inspections with a licensed plumber to detect hidden leaks or worn parts.
🏁 Conclusion
A toilet is one of the most important fixtures in any home or commercial building. Installing it properly ensures hygiene, comfort, and long-term reliability.
While the process may look straightforward, professional installation ensures everything—from alignment to sealing—is done with precision.
If you’re in Singapore and planning a toilet installation, replacement, or bathroom renovation, contact Alpha & Omega Trinity Pte Ltd. Our experienced team delivers quality workmanship, PUB-compliant installations, and fast service for residential and commercial clients.
📞 Call or WhatsApp: +65 8151 8857🌐 Website: www.aotrinitysg.com📧 Email: info@aotrinitysg.com
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