1. Symptoms and evidence
- Hand-wash sink drain/waste leaking.
- Top screw was tightened but leak continued.
- Photo shows top waste/strainer screw; the under-counter trap video was moved to the Bunk Lower Parliament shared drainage issue.
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Find parts, leak checks, washers, trap, or handover text
Streamlined issue brief
Hand-wash sink drain leak
Quick plumbing checklist after top waste screw tightening did not solve the leak.
OpenLeak persists after tightening visible top centre screw
2. Suspects
- Failed washer under waste fitting.
- Failed bedding seal under chrome flange.
- Loose/misaligned compression washer.
- Cracked trap/nut/tailpiece or side strain on pipework.
3. Expand resources
Manual / how-to / error reference
Standard UK basin/sink waste and trap system; size must be measured before parts purchase.
Troubleshooting tests
Dry everything, run small water amount, wrap tissue around each joint and identify first wet point.
Diagram / parts / sources
Likely parts: waste washer/seal kit, 32mm or 40mm bottle trap/P-trap, compression washers, or full waste fitting.
4. Updated solution/status
Open: inspect first wet point; replace waste seal, compression washer, or full trap kit as confirmed.
Issue history for this sink
Choose the problem type
This sink now has its own page. Future repeat faults should be added here under the same asset rather than mixed with refrigeration or postmix issues.
Open · 2026-05-25
Waste / drain leak after tightening top screw
Water is still leaking beneath the sink even after staff tightened the visible centre screw from above.
Open troubleshooting logBlocked trap / slow drain
No issue logged yet.
Tap / supply leak
No issue logged yet.
Overflow / wall pipe leak
No issue logged yet.
Sealant / sink bedding
Check if water leaks around the top waste flange.
Cracked trap / pipework
Check if plastic body or nuts are split from age/overtightening.
Current issue log · Sink waste leak
Troubleshooting sequence
1Dry everything fully with blue roll/tissue: underside of waste, trap nuts, vertical tail, horizontal pipe, wall connection.
2Run a small amount of water and watch with a torch. Find the first wet point, not just where water drips onto the floor.
3If water starts at the underside of the chrome waste, replace/reset the waste washer and bedding seal.
4If water starts at white plastic nuts, loosen/reseat the compression washer or replace the washer/trap.
5If any plastic body/nut is cracked or distorted, replace the full bottle trap / waste kit rather than keep tightening.
Most likely causes
Why tightening did not solve it
- The centre screw clamps the top waste, but it does not renew the rubber washers.
- If the lower rubber washer is twisted, hardened, split, or missing, tightening may not seal it.
- If the top flange bedding seal has failed, water can pass between the sink and waste fitting.
- If the leak is actually at the trap/compression nut, the top screw will not affect it.
- Overtightening can deform washers or crack plastic trap parts.
Next practical fix: identify the first wet point. If unclear, replace the waste seal kit and/or full trap kit — these are low-cost wear parts.
Leak-location checks
Use tissue to isolate the exact joint
- Top waste flange test: put dry tissue around the chrome waste inside the sink and underneath the sink bowl. Run water. If tissue around the underside of the waste gets wet first, the waste washer/bedding is leaking.
- Vertical tail / black pipe test: wrap tissue around the black vertical tailpiece and the upper white compression nut. If that wets first, reseat/replace that compression washer.
- Bottle trap nut test: wrap tissue around each white plastic nut on the trap. If one nut wets first, remove, clean, reseat the tapered washer, then hand-tighten plus a small nip only.
- Trap body test: inspect the white trap body for hairline cracks, especially near threads and elbows.
- Wall outlet test: check the pipe disappearing into the wall/black waste line. If wet starts there, the downstream compression or waste pipe may be loose or misaligned.
Do / don’t
Staff-safe checks
- ✅ Keep the floor dry and signposted.
- ✅ Hand-tighten plastic compression nuts only, then a small extra nip if needed.
- ✅ Clean hair, grease, limescale, and grit from washers and mating faces.
- ✅ Replace old washers rather than keep tightening.
- ❌ Do not keep overtightening the top screw.
- ❌ Do not use silicone as the only fix on a failed compression washer.
- ❌ Do not wrap PTFE tape around compression threads expecting it to seal; the washer should do the sealing.
Replacement parts to source
Likely UK plumbing parts
The remaining Loughborough evidence is the top waste/screw photo. The under-counter trap video that was previously shown here has been moved to the Bunk Lower Parliament shared drainage page, because it belongs to the ice machine / sink / glasswash drain system there. Measure before ordering: small hand-wash basins are often 32mm / 1¼ inch, while sink-style waste pipework is often 40mm / 1½ inch.
Waste washer / basin waste seal kit
Use if leak starts directly under the chrome top waste. Replace the rubber washer below the sink, foam/rubber top seal if fitted, and any fibre washer/backnut seal.
Screwfix · Thomas Dudley Basin Waste Seal Kit 3-piece Toolstation · Basin Mate 1¼ inchUse for 1¼ inch / 32mm basin waste sealing. Toolstation page checked at about £1.79; Screwfix search snippet showed about £2.39. Confirm live price/stock before buying.
32mm or 40mm bottle trap / P-trap
Use if leak starts from white plastic trap nuts/body. A full trap kit is often quicker than trying to find one old compression washer.
Screwfix · 40mm traps category Toolstation · Bottle trap category B&Q · FloPlast telescopic 40mm bottle trapCommon repair option: McAlpine or FloPlast 32mm/40mm trap. Confirm pipe size before buying.
Complete basin/sink waste fitting
Use if the chrome waste, centre screw, backnut, or top/bottom sealing faces are worn, corroded, distorted, or will not clamp squarely.
B&Q · Wastes and traps category Toolstation · Wastes categorySearch: unslotted basin waste · kitchen sink basket strainer waste · 1¼ / 1½ inch waste
Supplier preference: Screwfix, Toolstation and B&Q first for quick collection; then BES, City Plumbing, Wolseley, Travis Perkins, local plumbers merchants or Amazon as fallback. Prefer branded fittings such as McAlpine, FloPlast or Thomas Dudley. Prices change, so confirm live price and branch stock before sending staff.
Photo evidence
Current leak evidence
This page now only shows the Loughborough hand-wash sink top-waste photo. The under-counter trap video has been reorganised under the Bunk Lower Parliament shared drainage issue.
Video movedThe under-counter trap video belongs to Bunk Lower Parliament ice machine / sink / glasswash drainage and has been moved to that equipment page.
Engineer handover
Copy/paste brief
Use this when sending the job to a plumber/maintenance engineer.
Site details
- Venue
- Bunk Loughborough
- Address
- 18 Market Place, Loughborough LE11 3EA — confirm before dispatch
- Asset
- Hand-wash sink waste/drain and plastic trap assembly
- Issue
- Leak persists after visible top waste centre screw was tightened.
- Likely parts
- Waste seal/washer kit, 32mm or 40mm bottle trap/P-trap, compression washers, or complete waste fitting.