Leaking Shower or Bath: Damp on the Wall or Ceiling Below

Rung 1: Look, and compare the signs

Start with what you can see. RICS lists broken mastic seals around showers and plumbing leaks under baths among the causes of damp in homes, so the sealant line is the first place to look.

• Run a finger along the seal between the bath or shower tray and the wall. Gaps, black staining or sealant that lifts away are warning signs.
• Check the grout between wall tiles for cracks, missing sections or soft, crumbling areas.
• Look at the ceiling and wall in the room below or next to the bathroom for stains, flaking paint or a musty smell.
• Compare with leak signs from WaterSafe: damp patches on walls, floors or carpets, mould on ceilings and walls, a constant noise of flowing water, or loss of pressure.

Rung 2: Free checks to tell leak from condensation

WaterSafe describes a simple meter test if you are on a meter. Turn off all taps and appliances, wait 30 minutes for tanks and cisterns to fill, then note the reading including the red digits. Take a second reading after at least two hours, or overnight, with no water used. A higher second reading could mean a leak in the home.

Also notice the pattern. A wet patch that appears only after showers and fades could be steam settling on a cold surface. A patch that stays damp, grows or reappears in the same place after a dry spell is more likely water coming from somewhere. Take photos to compare day by day.

Rung 3: Fix the source, then dry it out

• If the seal is the problem, the usual repair is to remove the old sealant, let the area dry fully, and re-seal. If you are unsure, ask a tiler or bathroom fitter.
• If you suspect a leaking pipe or fitting, WaterSafe says to contact a plumber. Their guidance for a major leak is to turn off the water at the stop tap first.
• Do not paint over a damp stain. Let the area dry and confirm the source is fixed before redecorating.
• GOV.UK describes water leaking from waste and heating pipes, overflowing baths or sinks, or defective storage as a separate type of damp from condensation, so it needs a repair, not extra ventilation.

Rung 4: When mechanical help makes sense

Once the leak is repaired and the wall is dry, any remaining moisture may be everyday steam from showers and cooking. A good extractor fan and sensible habits come first. If humidity stays high in an owner-occupied home with a loft, a Dryzen system is one option: it is a loft-mounted dehumidifier and fresh air system with insulated ductwork to the central area or stairway. It is not suitable for rented homes unless the landlord authorises the changes, it needs a loft, and it does nothing for a leak or rising damp. It helps stop the conditions mould and dust mites need; existing mould must be cleaned off.

Mistakes that make it worse

• Sealing over a damp, dirty or mouldy seal rather than removing it first.
• Boxing in a bath or pipework so a slow leak cannot be seen.
• Assuming every bathroom stain is condensation and buying a dehumidifier first.
• Ignoring a patch that comes back in the same place.
• Painting over a stain with anti-mould paint before the cause is found.

In Chatham and the Medway Towns

We have no verified Medway figures on bathroom leaks, and we will not invent any. The pattern is the same in any home with a bath or shower above a ceiling, or against a party or external wall. Homes in the Medway Towns range from older terraces to newer estates, so check your own bathroom rather than assuming. See our town pages for Rainham, Strood and Borstal.

Questions we are asked

Related guides

• Damp Diagnosis Before You Pay for Treatment
• Bathroom and Kitchen Extraction That Actually Works
• Rising, Penetrating or Condensation Damp
• Wet Rot or Dry Rot? Soft Timber and the Damp Behind It

Local help

• Damp, mould and condensation help in Rainham
• Damp, mould and condensation help in Strood
• Damp, mould and condensation help in Borstal

Sources: WaterSafe: How do I know if I have a leak; WaterSafe: What should I do if I find a leak; RICS: Damp and mould consumer guide; GOV.UK: Understanding and addressing the health risks of damp and mould in the home.