Start by separating splash water from a plumbing leak
Water around a bath does not automatically mean a pipe has failed. Shower spray can escape past a screen, run along the bath edge or collect where sealant has separated from the wall. Dry the area completely, then test the bath in stages. Run the taps without filling it, then hold water in the bath, then release the waste, and finally use the shower if one is fitted. The stage at which water reappears usually gives a much better clue than looking at the final puddle.
The bath seal is a common weak point
Silicone between the bath and wall can split if it has aged, lost adhesion or the bath moves slightly when somebody stands in it. Water then runs behind tiles or panels and may appear on the floor or ceiling below. Simply applying fresh silicone over dirty old sealant rarely lasts. The failed material needs to be removed and the surfaces cleaned and dried. If the bath flexes excessively, support may need attention before resealing or the new joint can open again.
Waste fittings often leak only when the bath empties
A loose plughole fitting, failed sealing washer or leaking trap may stay dry while the bath is filling and begin leaking only when the waste is opened. Because a full bath releases a large volume quickly, even a small defect can wet the floor beneath. If an access panel can be removed without damage, watching the waste during a drain test is useful. Do not reach beneath a full bath if electrical equipment or inaccessible flooring makes the area unsafe.
Tap connections can hide at the difficult end
Bath taps are often mounted against a wall where their flexible tails and backnuts are hard to see. A slow leak from a tap connection can run down the back of the bath and mimic a failed seal. If the water appears while the taps are running but before the bath has filled, this becomes more likely. Mixer shower hoses and deck-mounted controls create additional joints that can also seep. Access can be the main challenge, particularly on fully tiled bath panels.
Water below the bath should not be left to find its own way out
Repeated wetting can swell chipboard floors, damage plasterboard ceilings and encourage mould in enclosed voids. A stain below may remain small for some time even while the timber around the bath is staying damp. If the source cannot be identified from normal use tests, a plumber may need to open a panel or create controlled access. It is better to expose a small area deliberately than to let water decide where the damage appears next.
What to tell the plumber
Explain whether the leak occurs while filling, while somebody is showering, when the plug is released or at random. Mention any recent resealing, new taps or bath movement. Photographs of the bath edge, taps and any ceiling stain below are useful. If the bath panel is tiled or fixed, say so because access may affect the quotation. A contractor can then allow for investigation rather than assuming every bath leak is a five-minute silicone repair.
After the repair, test the bath in the same stages again
A bath leak should be proved dry under the conditions that originally caused it. If the fault appeared during showering, run the shower and direct water around the screen and bath edge while the repaired area is observed. If it leaked when emptying, release a reasonably full bath and check the waste and trap. A quick trickle from the tap is not the same test. Keep the access panel off until the plumbing has been seen to stay dry. Where old water has soaked the floor or ceiling below, allow drying time before sealing everything up. If a flexible bath was part of the problem, make sure movement has been dealt with as well as the silicone. A sound repair should survive normal use, not just look neat immediately after the plumber leaves.
This page is general guidance about why is water leaking around my bath; the cause in an individual property depends on the actual plumbing arrangement.