Make It Safe and Stop the Water

Before investigating a leaking bath, prevent further water damage and make sure the area is safe to inspect.

• Stop using the bath, taps and shower until you have a better idea of where the leak is coming from.
• If water appears to be escaping from a supply connection, close the relevant isolation valve if it is accessible and safe to operate. If you cannot isolate the affected supply, use the main stopcock if you can reach it safely.
• The main stopcock is often under the kitchen sink, near the point where the water supply enters the property, or in another accessible service location. Locations vary between homes.
• If water is coming through the ceiling below, keep people clear of the affected area. Do not touch wet light fittings, switches or electrical equipment.
• Only switch off electricity at the consumer unit if you can reach it without approaching water or wet equipment. If it is wet or unsafe to approach, keep clear and contact a qualified electrician.
• Use towels or a bucket to contain water only where it is safe. Do not stand in water near electrical equipment.

Find Where the Leak Is Coming From

Different faults can produce similar damp patches. A careful inspection helps you distinguish a leaking supply connection from a waste, overflow or bath seal problem.

1. Dry the accessible bath surfaces, taps, waste area and surrounding floor. If water is actively escaping or there is damage below, stop and arrange professional help rather than continuing the tests.
2. Place small strips of kitchen roll near accessible connections, beneath the taps and around the waste. Keep paper away from electrical equipment and hot surfaces.
3. If the area is safe and the water supply can be controlled, briefly run the taps with the plug out. Watch for the first sign of water beneath the tap assembly or at accessible pipe joints.
4. If no leak appears, add a small amount of water to the bath while monitoring the waste outlet and the accessible area beneath it. Stop if any leak develops.
5. If the bath remains dry, increase the water level gradually while watching for leaks. Filling to just below the overflow does not test the overflow connection itself.
6. Only if the earlier checks remain dry and it is safe to proceed, allow water to enter the overflow opening while monitoring its accessible connection. Stop immediately if water appears outside the intended drainage route.
7. If the bath remains watertight, release the water and watch the waste and trap connections while it drains. A leak that appears only during draining may indicate a waste or drain connection problem.
8. If the leak appears only after showering, inspect the accessible bath-to-wall seal, grout and shower fittings. Do not spray water near electrical equipment or deliberately soak a suspected leak area.

The first place where water appears is a useful clue, but water can travel along pipework, flooring and the underside of the bath before becoming visible. A damp patch does not always sit directly beneath the fault.

Fix the Leak at the Source

Only attempt a repair when you have identified a likely cause, can safely access the fitting and know how it is designed to seal. A bath panel may provide access to the pipework, but its fixing method varies between installations.

Leaking waste or overflow

• Stop using the bath and ensure the relevant water is no longer entering the waste or overflow. Keep the area below accessible for inspection.
• Inspect the accessible waste, trap and overflow connections with a torch. Do not loosen a connection while water is flowing through it.
• If a compatible slip nut is visibly loose, follow the fitting manufacturer's instructions and tighten it carefully. Do not assume every fitting needs an additional quarter turn, and avoid overtightening plastic components.
• If a joint continues to leak, the washer, seal or fitting may be damaged or incorrectly seated. Replace parts only with compatible components and refit them according to the manufacturer's instructions.
• A leak around the plughole may involve the waste body's seal against the bath as well as the connection underneath. If the waste assembly needs removal, take care not to damage the bath or drainage fittings. Seek professional help if access is difficult or the fitting is corroded.

Leaking tap connectors or tap body

• Isolate the relevant water supply before opening any plumbing joint. Operate the taps only as appropriate to relieve residual pressure, and be aware that hot water may remain in the pipework.
• Inspect accessible tap connectors and joints for signs of moisture. A leaking connection may need a replacement washer, O-ring, connector or damaged fitting rather than additional tightening.
• Use a replacement washer or seal that matches the specific fitting. Do not assume every flexible hose or tap connector contains a replaceable fibre washer.
• A dripping spout may indicate a worn washer or ceramic cartridge, depending on the tap design. Follow the manufacturer's repair instructions or use a plumber if the mechanism is unfamiliar. See our tap repair service for further assistance.
• Use PTFE tape only on joints designed to seal through their threads and where the fitting manufacturer recommends it. Do not add tape indiscriminately to compression fittings, O-ring connections or joints that seal with a washer.

Small crack or surface damage in an acrylic bath

• Stop using the bath if a crack is leaking or the base feels unstable. Water can escape beneath the surface even when a crack looks small.
• A compatible repair kit may be suitable for minor cosmetic surface damage if the bath manufacturer permits that type of repair. Follow the kit instructions and prepare the surface as specified.
• Cracks around the waste, leaking splits, structural damage, significant flexing or a poorly supported bath need professional assessment. Replacement may be necessary, but the correct solution depends on the bath material, the damage and the supporting structure.

Reseal the Bath Properly

A failed bath-to-wall seal can allow splashed or shower water to pass behind the bath and damage surrounding materials. Resealing is appropriate when the existing seal is cracked, detached, deteriorated or otherwise identified as the likely source of water ingress. It will not repair a leaking waste, overflow or supply pipe.

1. Check the bath and sealant instructions. Confirm that the new sanitary silicone is suitable for the bath material, tiles and intended joint. Follow the manufacturer's instructions for bath loading during application and curing.
2. Prepare the area. Stop using the bath and remove the old silicone carefully with a suitable sealant remover or scraper. Avoid scratching the bath, damaging the tiles or cutting into concealed pipework.
3. Clean and dry the surfaces. Use a cleaner compatible with the bath, tiles and selected sealant. Do not use white spirit or another solvent unless the manufacturers confirm it is suitable. Remove all residue and allow the joint to dry completely.
4. Position the bath as instructed. Some installations require the bath to be filled before sealing to account for movement under load. Follow the bath and sealant manufacturers' guidance rather than assuming every bath should be filled in the same way.
5. Apply the silicone. Use masking tape if needed to create a neat edge. Apply a continuous bead of suitable sanitary silicone, ensuring the joint is properly filled. Smooth it using the sealant manufacturer's recommended method and remove masking tape before the silicone skins over, if the product instructions advise this.
6. Allow it to cure fully. Keep the bath in the specified position and avoid water exposure until the sealant has cured for the period stated on the cartridge. Do not assume every product is ready for use after 24 hours.

Test the Repair Carefully

Once the repair is complete and any sealant has cured, test the affected component in a controlled way. Do not recreate a condition that previously caused significant water damage.

• If you isolated the water supply, reopen the relevant valve slowly when it is safe to do so. Check the joints you worked on for moisture.
• For a tap connection repair, run the affected tap briefly while checking the accessible connection. Stop if water appears.
• For a waste or trap repair, add a small amount of water first and inspect the joint. If it remains dry, increase the amount gradually and check again while the bath drains.
• For an overflow repair, test the overflow only when it is safe and you can monitor the connection. Stop immediately if water escapes.
• For a resealed bath, wait until the sealant has fully cured before exposing it to water. Then check for leaks during normal use without deliberately soaking the surrounding area.
• Inspect the accessible pipework, surrounding floor and ceiling below, if applicable. Some leaks appear only after water has travelled through the structure, so check again later.
• Refit the bath panel only when the relevant connections have been checked and the repair remains dry. If you need further monitoring, leave safe access available.

If the leak returns, the original diagnosis may have been incomplete or another fault may be present. Stop using the bath if necessary and arrange a professional inspection rather than repeatedly tightening fittings or applying more silicone.