A leaking pipe is no joke. First you have to stop the water – so you need to know where to turn if off – and then to make some kind of emergency repair, even if it’s just a holding operation.

Water in this pipe(and others leading from it) is under mains pressure, leaks from it will be particularly serious. It enters the house underground, and from there leads either to all the cold taps and a water heating system, or to just the cold tap in the kitchen and to a cold water storage tank.

Leaks can result from a number of causes. Pipework may have been forced or strained at some point, resulting in a leak at one of the fittings connecting the lengths of pipe together, or in a fracture at a bend.

Corrosion within pipes may lead to pin-holes in pipe lengths, while frost damage can lead to bursts and splits in pipes and to leaks at fittings caused by ice forcing the fitting open. Whatever the cause, cutting off the water supply to the affected pipe is the first vital step. 1 Cold water supply pipes connected directly to the mains: in the UK these pipes usually only supply the kitchen cold tap. The cold water storage tank and sometimes instantaneous water heaters. In Australia and other countries, the pipes may supply cold water taps and the hot water storage cylinder. The simple way of deciding whether any pipe or tap is supplied directly by the mains is by the pressure – taps supplied from a tank are what’s known as gravity-fed and the pressure of water is relatively low compared to mains pressure. 2 Cold water supply pipes from a cold water storage tank: in the UK these pipes usually supply the bathroom cold taps, the WC cistern and the hot water cylinder.

To close off the water supply in these pipes there’s often a stop-valve immediately alongside the cold water tank where the pipe exits. Turn this off first and then open all cold water taps. They’ll run dry almost immediately. If there isn’t a stop-valve, you have to drain the whole tank. So first you stop water entering the tank by either turning off the mains or by tying up the ball-valve in the tank so that it remains closed. Then you open all the taps in the house. 3 Hot water pipes: these are all supplied from a hot water cylinder, which in turn gets its cold water either from the cold tank or from the mains.

Since hot water leaves the hot water storage cylinder from the top, it’s only the pressure of water going in at the bottom of the cylinder that forces the water out. Turn off the supply of cold water (either at the cold water tank, or at the mains) and you stop the flow. In this sort of situation the hot water cylinder remains full. If for any reason you need to drain this as well, use the drain cock near the bottom. It’s essential in this case to turn off either the immersion heater or boiler,

To turn off the water, look for the mains stop-valves. There may. In fact, be two: one inside the house where the mains pipe enters (under the kitchen sink, in the utility room, or even under the stairs); the other outside -either just inside the boundary of the property (near to a water meter, if you have one), or under the footpath outside the garden fence. Outdoor stop-valves may be set as much as a metre (3 ft) down beneath a hinged cover or metal plate, and you may need a special ‘key’ which is really just a long rod with a square socket on the end which fits over the tap to turn it. In most cases, however, it’s simply a matter of reaching down to turn it off by hand or with a wrench. Some outdoor stop-valves also control a neighbour’s water supply, so do warn them if you’re turning it off.

The stop-valve inside will either be a wheel type or an ordinary T-shaped type. The only possible complication is if it hasn’t been touched for years and is stuck fast. A little penetrating oil and tapping it with a hammer will usually loosen it sufficiently. (It’s worth closing the stop-valve now and again to see that it doesn’t get stuck.)


Make sure the family knows where the mains stop tap is.

– do not force the handle if it has seized up — it could break it off.

– use hammer or wrench to tap the fitting while pouring penetrating oil down spindle.

– if you can’t free it call the water authority emergency service — they can turn the water off where your supply pipe leaves the mains.

– don’t reopen stop valve fully when turning on the supply until a permanent pipe repair is made. This reduces water pressure on a temporary seal.


If you don’t have the right materials to hand try this:

– bandage insulating tape round the pipe and hole

– cover with a 150mm (6in) piece of garden hosepipe slit along its length and tie with wire at each end, twisting ends of wire together with pliers

– wrap more tape tightly over this.

• One type of repair kit is based on a two-part epoxy resin plastic putty supplied as two strips of differently-coloured putty in an airtight pack. When the strips are thoroughly kneaded together the putty is packed firmly round the pipe, where it will harden to form a seal. However, this hardening process takes up to 24 hours and the water supply will have to remain off for this period. (If you don’t need to use all the pack in one go, reseal it immediately).

Equal amounts of putty should always be used and mixed together thoroughly until a uniform colour results, otherwise it won’t harden properly. It’s also essential that the pipe or joint is scrupulously rubbed down and cleaned with methylated spirit or nail polish remover. This will ensure a good bond between the putty and the metal.

• One of the most valuable aids is a multi-size pipe repair clamp which has the added advantage of being reusable. It consists of a rubber pad which fits over the hole (for this repair it’s not necessary to turn off the water) and a metal clamp which draws the rubber tightly against the pipe when it is screwed in place.

Position the pad and one side of the clamp over the hole, and link the two parts of the clamp together, making sure that the pad is still in place. Tighten the wing nut fully. If the position of the hole makes this difficult, use blocks of wood to hold the pipe away from the wall. This method of repair cannot, of course, be used to mend leaks occurring at fittings.

• Another proprietary product uses a two-part sticky tape system which builds up waterproof layers over the leak — in the true sense this does form an instant repair. The area round the leak should be dried and cleaned and then the first of the tapes is wrapped tightly round the pipe, covering the leak and 25mm (1 in) either side of it. Then 150mm strips of the second tape, with the backing film removed, are stuck to the pipe and stretched as they are wound round, each turn overlapping the previous one by about half the width of the tape. This covering should extend 25mm beyond either end of the first layer of tape. The job is completed by wrapping the first tape over all the repair.

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