Domakihub How to Fit a Shower Waste Trap: A Step-by-Step Guide
Get a leak-free seal first time with the right trap, a little sealant, and five clear steps.
Reviewed by Domakihub home & decor pros · 2026-06-23 · 5 min read
Fitting a shower waste trap is one of those plumbing jobs that looks intimidating but is well within reach of a careful DIYer — provided your pipework is already in place. The video above from Victoria Plum walks through the process visually, while this guide breaks it down into five ordered steps with the details that matter for homes, holiday rentals, and hotel bathrooms across Greece. A properly seated trap stops bad smells, prevents leaks, and keeps your shower tray draining freely for years.
What a Shower Waste Trap Actually Does
A shower waste trap sits directly beneath the outlet hole in the shower tray. It holds a small volume of water at all times, and that water plug is what physically blocks drain gases and odours from rising back up through the tray. Without a working trap — or with one that has dried out after a property sits empty — you will smell sewer gases in the bathroom.
In Greece, holiday villas and rental apartments are particularly prone to dried-out traps after weeks without use. Re-wetting or replacing the trap is usually the first thing to check when a shower smells.
Choosing the Right Trap for Your Tray
Shower waste traps come in two main families: bottle traps (a single-piece unit that screws beneath the tray outlet) and McAlpine-style combined waste-and-trap units where the grate, body, and trap integrate into one. For low-profile or flat-access traps used with modern slimline trays, a shallow-seal trap — sometimes called a square trap or 'bath-shower trap' — is needed because there is not enough floor void for a standard depth unit.
Always confirm the outlet size of your shower tray before buying: 90 mm is the most common standard in Europe, but 52 mm and 60 mm outlets exist on some older Greek-market trays. Also confirm the diameter of your waste pipe — 40 mm or 50 mm — so the trap's outlet matches without an adaptor.
How to Fit a Shower Waste Trap: 5 Steps
- 1
Remove the old trap and clean the outlet recess
Turn off the water supply to the shower if a valve is present, then unscrew the chrome or plastic grate cover from the tray outlet. Unscrew or unclip the old trap body from underneath — on a raised tray you can reach it from below; on a floor-level tray you may need to tilt the tray slightly or access a side panel. Remove any old silicone, plumber's putty, or corroded rubber seals from both the tray underside and the top of the outlet recess. A clean, dry, grease-free surface is essential for a good new seal.
- 2
Fit the new waste grate to the tray outlet
Apply a thin, even bead of sanitary-grade silicone sealant or plumber's putty around the underside flange of the new waste grate — this is the chrome ring that sits visible in the tray floor. Press it firmly and centrally into the outlet hole from above, making sure it sits flush and level with the tray surface. If your trap kit includes a flat rubber sealing gasket, fit that instead of sealant between the flange and the tray. Do not overtighten at this stage.
- 3
Attach the trap body from underneath
From below the tray, slide the rubber compression washer onto the threaded tail of the waste outlet (if supplied separately), then thread the trap body up onto the outlet tail by hand. Once hand-tight, use the correct spanner or the manufacturer's plastic tool to nip it up a further quarter-turn — enough to compress the washer and lock the trap, but not so much that you crack the plastic body or strip the thread. The trap's outlet pipe should point in the direction of your waste pipe run at this point.
- 4
Connect the trap outlet to the waste pipe
Push — or twist and lock, depending on the fitting type — the trap's 40 mm or 50 mm outlet spigot into the waste pipe. Solvent-weld connections require ABS cleaner and cement applied to both surfaces, then a firm push and a quarter-turn to set. Push-fit connections simply click in. Check that the pipe run has a continuous fall toward the stack of at least 18–45 mm per metre — too little fall causes slow draining, too steep causes the water to race ahead and leave the trap dry. Secure the pipe to the floor or wall with a pipe clip within 300 mm of the trap outlet.
- 5
Test for leaks before sealing the tray surround
Run water into the shower tray for a full two minutes, watching carefully underneath (torch and mirror help on low trays) for any drips at the grate-to-tray joint, at the trap body, and at the waste pipe connection. Fix any weep now — do not tile or silicone the tray perimeter until the trap is confirmed dry. Once the test passes, apply a neat bead of sanitary silicone around the tray grate flange on the top surface if there is any visible gap, and smooth with a wetted finger. Allow 24 hours cure before the shower is used.
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FAQ
- Do I need a plumber to fit a shower waste trap in Greece?
- Fitting or replacing a shower waste trap is a permitted DIY task in Greece — it does not involve pressurised mains pipework or gas. However, if the waste pipe needs to be cut into or re-routed, or if you are connecting to a shared soil stack in a block of flats, it is wise to have a licensed plumber confirm the work. Holiday rental owners should also check their building insurance, as some policies require professional installation for plumbing work.
- Why does my shower smell even though the trap looks fitted?
- The most common cause in Greek holiday homes is a dried-out water seal: if the shower has not been used for several weeks, the standing water in the trap evaporates and the gas plug disappears. Run the shower for 30 seconds to refill it. If the smell persists, the trap may be cracked, its rubber seal may have perished, or the grate-to-tray joint may have a gap letting gases bypass the trap entirely. A shallow-seal trap in a low-profile tray can also lose its seal more quickly than a deeper bottle trap.
- What is the minimum depth for a shower waste trap in a slimline tray?
- Standard traps require around 70–90 mm of floor void below the tray outlet. For contemporary slimline trays with only 30–50 mm of clearance — very common in Greek new-build apartments — you need a low-profile or 'flat' trap, sometimes branded as a 50 mm seal trap. These are widely available from plumbing merchants and maintain a 50 mm water seal depth despite the compact body, which meets the minimum seal requirement under European standard EN 274.