Turn the shower off, dry the head with a towel, and come back in half an hour. Water left in the hose and head drains out in the first few minutes, longer on a big rainfall head, and then it stops. If the head is still dripping steadily after thirty minutes, the water is coming through a valve that is not closing fully, and it will not get better on its own.
Draining or passing: what the drip tells you
| What you see | What it usually is |
|---|
| Drips for a few minutes after use, then stops | Water left in the hose and head draining out. Normal. |
| A steady drip that never stops, day or night | The valve is passing: a worn or scaled cartridge, or a perished washer or seal |
| Dripping gets worse at night or when nothing else is running | The same fault. Supply pressure rises when the house is quiet and pushes more past a worn seal. |
| Dripping from the head only after the bath has been filled | The diverter on a bath shower mixer not seating fully |
| Electric shower dripping with the unit switched off | The solenoid valve inside the unit not closing, usually scale or grit |
| Water running from behind the handle, the trim plate or the wall, not the head | A leak from the valve body or its connections, which is a different and more urgent problem |
The last row is the one to take seriously. A dripping head wastes water; a leaking valve body puts water into the wall.
Why a mixer shower starts dripping
Most showers in London homes are mixers, fed with hot and cold and blended inside the valve. How they shut off depends on the type.
Thermostatic bar and concealed valves
Most thermostatic valves have two controls: one for temperature, one for flow. The flow side is usually a ceramic disc cartridge, two polished discs that slide over each other to open and close the water. Once they are scratched by grit or furred with scale they stop sealing, and a thin stream gets through with the handle fully off. That is the drip at the head.
Single-control valves, where one handle turns the water on and then sets the temperature, do both jobs with one cartridge, so the drip and a wandering temperature often arrive together. If your shower has lost its hot water as well, no hot water in the shower covers the other half of that fault.
Manual mixers and older two-handle valves
A lever mixer uses a ceramic cartridge in the same way. Older valves with separate hot and cold handles that turn several times before they close usually have rubber washers on brass seats instead, exactly like a traditional tap. A perished washer or a seat pitted by scale lets water past, and a new washer on a pitted seat will start dripping again within months. How to change a tap washer explains how to tell a washer from a cartridge before you buy parts.
Bath shower mixers
Where the shower runs off the bath taps, a diverter sends water either to the spout or up to the head. A worn diverter seal lets some water up the hose while the bath fills, and leaves the head dripping afterwards. The diverter is usually a separate part from the tap cartridges, so it can be replaced on its own.
Why London water makes it worse
A ceramic cartridge is built to fine tolerances, and a small deposit of scale on one disc is enough to stop the pair sealing. It is the same reason cylinders and immersion heaters fail early here; hard water scale in London goes into that. A descaled cartridge that stops dripping for a week usually starts again, because the discs are already marked.
High supply pressure makes a worn seal pass sooner. If taps bang when they shut, read water pressure too high before a new cartridge goes in, or the same pressure will wear that one too.
Electric showers
An electric shower heats cold mains water inside the unit, and a solenoid valve opens and closes the water when you press start and stop. If scale or grit stops the solenoid closing, the shower drips with the unit off. That is a component inside a live appliance: switch it off at the pull cord or fused switch, leave the cover on, and call the manufacturer, a shower engineer or an electrician.
Checks you can do safely
- Do the thirty-minute wait with the head dried off first.
- Make sure the control is fully off. On some thermostatic valves the flow handle has a firm stop and a softer point before it. Turn it gently to the end of its travel and see if the drip stops.
- Look for isolation valves. Many bar valves have a screwdriver slot in each inlet elbow. Turn both so the slots sit across the pipe. If the drip stops once the head has drained, the valve is the source, and you can leave them closed until the repair.
- If there are no isolators, the valve can only be isolated at the stopcock for the cold side and at the cylinder or boiler for the hot. How to turn off your water supply shows where those are.
- Look behind and below the shower. Dark grout around the valve, a stain on the ceiling underneath, or loose tiles near the trim plate are signs the valve is leaking into the wall as well as through the head.
Stop before taking the valve apart unless it is an exposed bar valve with working isolators and you have the right cartridge for the make and model. A cartridge refitted with a seal out of place leaks inside the valve body, and on a concealed valve that means inside the wall.
Is a dripping shower head costing you much?
A single drip is small, but it runs every hour of the day, and if it is coming through the hot side you are paying to heat water that goes straight down the drain. If your metered bill has crept up, the overnight test in how to read your water meter to find a leak tells you whether anything else is losing water too.
When the drip is also a leak
Most dripping shower heads are just a worn cartridge. The ones that turn into a ceiling repair are concealed valves, which sit inside the wall at full supply pressure all day. The same wear that lets water through to the head can let it out past the body seals and the connections behind the tiles.
If there is any mark on the ceiling below, or water appears when nobody has used the bathroom, shower leaking through the ceiling has a simple timing test that separates a valve leak from a tray, seal or tile leak in a few hours. If the shower only leaks while it is running, a leaking shower: tray, seal, waste or pipe goes through the four usual faults in order.
What the repair involves
On an exposed valve, both supplies are isolated and the flow cartridge or washer is replaced with the part for that make and model. The temperature cartridge and inlet filters are checked while the valve is open, the temperature stop is reset against a thermometer, and the valve is watched with the water back on to make sure it shuts off completely. How to change a tap cartridge covers identifying and swapping the part if you are doing it yourself.
On a concealed valve, many cartridges can be reached from the front once the trim plate is off, and the job is the same. Where the valve body itself is weeping, or the connections behind it have been leaking, the wall has to be opened. We find the wet area first so the tiling is opened at one point rather than stripped, repair or replace the valve, pressure test it, and then put the wall back: tanking, tiles and grout, and the ceiling below if it has been wet. That is our bathroom and shower leak repair service.
We charge £150 per hour, agreed before we attend, with no call-out fee. If the job turns into a hidden leak and we do not find it, you do not pay for the time spent looking. The pricing page sets out how the total is worked out.
When it is not us
- An exposed bar valve with its own isolators and nothing leaking. A cartridge change is a job any competent plumber can do, and plenty of homeowners do it themselves with the right part.
- An electric shower that drips when switched off. The manufacturer, a shower engineer or an electrician.
- You rent. Report it to your landlord in writing. It is a repair to the water installation and it may be running up a metered bill you are paying.
Call us when the valve is buried in the wall, when there is a mark on the ceiling below, or when a new cartridge has already gone in and the drip came back. Book an engineer or call the number at the top of this page, and tell us the make of the shower if you can find it on the trim or the handle. That usually tells us which parts to bring.
