Bathroom Snagging Checklist: What to Inspect in Your New Build

Bathrooms are the number one source of warranty claims in new-build homes. A poorly sealed shower tray, a leaking waste pipe behind a bath panel, or failed mastic around a basin can cause thousands of pounds of damage to floors, ceilings, and the rooms below.

This bathroom snagging checklist covers 28 specific defects to inspect before you complete on your new build. Every item is something you can check yourself with your eyes, your hands, and a few minutes of running water. Work through it systematically and you will catch the problems that lead to the most expensive post-completion repairs.

If you have not already done your full property inspection, start with The Complete New Build Snagging Checklist — the pillar guide that covers every room.

Why Bathrooms Need Special Attention

Bathrooms combine water, drainage, sealed surfaces, and ventilation in a small space — and every element has to be right. A single gap in the sealant around a shower tray can let water track beneath it for months before anyone notices, rotting the subfloor and staining the ceiling below.

According to NHBC data, water penetration from bathrooms is among the most frequently reported new build bathroom problems in the first two years of warranty. Remediation typically costs £300 for resealing up to £3,000+ where water has damaged structural timber or ceilings. Catching bathroom defects new build during your snagging inspection — before completion — is when you have the strongest leverage to get them fixed at the developer's expense.

The Bathroom Snagging Checklist

Sanitaryware

1. Toilet flushes fully and refills correctly. Flush at least twice. The bowl should empty completely, the cistern should refill within a minute, and the flush valve should shut off cleanly with no continuous trickle.

2. Toilet is firmly fixed to the floor. Sit on the toilet and shift your weight gently side to side. It should not rock. A loose toilet will eventually break the seal at the waste pipe, causing leaks beneath the floor.

3. Toilet seat is secure and aligned. Lift and lower the seat. It should sit centrally on the bowl without sliding.

4. Basin is stable and level. Press down on opposite edges. It should not flex or rock. Fill halfway — the water line should be parallel to the rim.

5. Basin is free from chips, scratches, and staining. Inspect the entire surface including inside the bowl, the rim, and the pedestal or vanity mount.

6. Bath is level and does not flex. Step into the bath carefully. It should feel solid with no flexing or creaking. Fill it a quarter full — the water should sit level.

7. Bath panel is fitted securely and can be removed. The panel should be flush, undamaged, and removable for access to pipework. If it is siliconed shut, flag it immediately.

Shower and Bath Enclosure

8. Shower tray is level and does not flex. Step onto the tray carefully. Pour water across the surface — it should flow towards the drain, not pool in the centre or corners.

9. Shower screen or door seals properly. Close fully and run the shower for two minutes at full power. Check the floor outside — there should be no water escaping around the seals.

10. Shower pressure and temperature are adequate. The water should reach a comfortable temperature within 30 seconds. The thermostatic valve should prevent scalding and maintain consistent temperature.

11. Shower drainage speed. Let water accumulate, then check it drains within a few seconds. Slow drainage suggests a trap issue or incorrect fall on the waste pipe.

12. Mastic sealant around the shower tray is continuous and intact. Inspect where the tray meets the wall on all sides. The bead should be unbroken and firmly bonded to both surfaces. Gaps here are the single most common cause of water damage in new-build bathrooms.

13. Mastic sealant around the bath is continuous and intact. Fill the bath with 50mm of water before checking — the weight pulls the bath down slightly, revealing gaps invisible when the bath is empty.

Tiling

14. Grout lines are consistent and fully filled. Lines should be straight, evenly spaced, and completely filled. Hollow or crumbling grout lets moisture behind the tiles and into the wall.

15. No cracked, chipped, or hollow tiles. Inspect every tile. Tap each lightly with your knuckle — a hollow sound means the tile is not fully bonded. In wet areas, hollow tiles will admit water and may eventually fall.

16. Tiles are aligned and level. Sight along the rows. Lippage should be minimal. Check tile cuts around pipes and edges — they should be neat, not rough or oversized.

17. Tile trim and edging is secure. Edge trim should be firmly fixed, straight, and free from sharp edges. Check where vertical and horizontal trims meet — gaps here admit moisture.

Plumbing

18. Hot and cold taps are on the correct sides. Cold should be on the right, hot on the left. This is a building regulation requirement and is surprisingly often reversed in new builds.

19. Water pressure is adequate at all outlets. Run the basin taps, bath taps, and shower simultaneously. Pressure should remain reasonable at each outlet.

20. No leaks under the basin. Run both taps for 30 seconds, then inspect all pipework beneath the basin. Lay tissue paper around joints — if it gets damp, there is a leak.

21. Bath waste and overflow are working. Fill the bath until water reaches the overflow. It should drain through without leaking behind the panel. Release the plug — the bath should empty fully.

22. No visible leaks behind the bath panel. Remove the panel and inspect pipework, the trap, and the underside of the bath. Look for damp patches, standing water, or white mineral deposits on joints.

Ventilation

23. Extractor fan is operational. Turn the fan on and hold tissue near the grille — it should be drawn towards the fan. It should run quietly without rattling.

24. Extractor fan overrun timer is set correctly. If linked to the light switch, the fan should continue running for 15–20 minutes after the light is turned off. This is a building regulation requirement for bathrooms without an openable window.

25. Window opens and closes freely (if present). Check the mechanism, hinges, and locking hardware. The window should seal tightly when closed. Trickle vents should open and close smoothly.

Flooring

26. Floor is level, waterproof, and free from damage. Walk the entire floor. Feel for soft spots or unevenness — these may indicate a subfloor issue. Check for scratches, chips, and staining from construction traffic.

27. Floor is sealed at all edges. Where the floor meets the wall, bath, shower tray, and toilet base, there should be a sealant bead or cove trim. Any gap is a route for water to reach the subfloor.

28. Threshold strip is fitted and secure. Where the bathroom floor meets the adjacent room, the strip should be flat, firmly fixed, and not a trip hazard. It also acts as a moisture barrier.

How to Record Your Bathroom Snags

For every defect you find:

1. Photograph it — wide shot showing location, close-up showing the defect.
2. Note the exact location — which bathroom, which wall or fitting.
3. Describe the issue — what is wrong and why it needs fixing.

Use Snaggit to photograph and tag each bathroom snag as you go. The app walks you through each area, lets you annotate photos on the spot, and generates a professional report you can send straight to your developer's aftercare team.

What to Do Next

Once your bathroom inspection is complete, work through the rest of your home. If you have not done your kitchen yet, the Kitchen Snagging Checklist covers 30 defects specific to kitchens — including many of the same plumbing and tiling issues.

For the full property inspection, return to The Complete New Build Snagging Checklist and work through every room before your completion date.

Do not underestimate bathroom defects. A £5 tube of mastic costs nothing compared to the £3,000 ceiling repair you will face if a shower tray leaks undetected for six months. Inspect now, report now, and get it fixed before you complete.