Electric shower leaking from the unit

What it usually means

An electric shower has exactly four places water can escape, and the first thing to do is work out which one you are looking at, because they run from trivial to stop-now. Start at the top. Water running down from the handset, the hose or the point where the hose screws onto the unit is a fitting: a washer that has flattened, a hose that has split near the ferrule, a spray plate that has cracked, or a thread that was not tightened after the last time the hose came off to be descaled. None of it involves the inside of the unit and all of it is a bathroom-shop part. It can look alarming because the water runs down the outside of the casing and drips off the bottom, which is why so many searches for a leaking unit are really a leaking hose connection. Dry the whole thing, run the shower for a minute and watch where the first drop appears.

The second place is a small plastic tube or spout on the underside of the unit, and water from there is not a leak in the ordinary sense. Nearly every electric shower has a pressure relief device, a plug that blows out if pressure builds inside the heater tank, and the tube is where it discharges. It operates when the outlet is restricted while the elements are on, which in practice means a scaled handset or a kinked hose that has made the water in the tank flash towards steam. Redring describe the safety pressure relief on their showers as a replacement part rather than something that reseals, and the same is true across the category: once it has gone the shower will run water from the tube every time it is used until the device is replaced, and Redring advise replacing the handset and hose at the same time because a blocked outlet is the usual reason it operated. The all-brands page on the pressure relief device covers it in detail. What matters here is that a shower discharging from underneath is telling you it has already prevented something worse, and it should not be run again until it is fixed.

The third and fourth places are the ones to take seriously. Water from the inlet fitting, where the cold pipe enters, is a compression joint or an inlet filter cap that has been disturbed, and it is competent-person work because that fitting sits centimetres from the terminal block. Water from the casing itself, seeping from the seams, weeping from around the buttons or pooling behind the cover with no visible source, means water is inside an enclosure that also contains a 40-amp terminal block, the element connections and a control board. The manufacturers are of one mind about that and this site follows them: stop using the shower, switch it off at the pull cord or the isolator, and do not switch it back on until it has been opened by someone qualified. A leak inside the casing is also the most common reason an electric shower starts tripping the RCD, so if the trips began around the time the drips did, they are one fault and not two.

The temptation with any of these is to keep using the shower because it still works. With a hose that is fine. With a pressure relief discharge or water in the casing it is not, because the shower is either running with a spent safety device or running with water where the electricity is, and the cost of the repair is the same whether you stop today or after the next trip.