Cold Water Services

Prior to the reorganisation of local government that took place on 1 April 1974, the responsibility for the provision of water supplies rested either with the local Borough or District Council or with one of the many statutory water undertakings. Since that date all-purpose Regional Water Authorities have been responsible for water supply, sewerage and sewage disposal. In many areas however the former water authority continues to act in that capacity as agent for the regional authority.

Water is distributed from the Authority’s reservoirs by means of underground water mains, usually of iron suitably protected against corrosion. A branch communication pipe connects the main to a Water Authority stop-cock at the boundary of each property. It is at this stop-cock that the householder’s responsibility for his water services begins.

The stop-cock will be found in a purpose-made pit, 3ft or more deep, with a hinged metal cover. Unlike the stop-cocks within the house, this one will probably have, instead of the conventional crutch or wheel head, a specially designed shank that can be turned only by means of one of the Authority’s turn-keys. This enables water supply to be turned off when the house is unoccupied, or in the event of the occupier failing to pay his water rate!

From this stop-cock a service pipe is taken to within the house curtilage. This pipe should rise slightly throughout its length to permit any air bubbles to escape but, as a frost precaution, must be kept at least 0.82 metres below ground level.

The material of which the pipe is made will depend largely upon the date of its installation. Prior to the mid-1930s it would certainly have been of lead. Nowadays it is more likely to be of dead-soft temper copper tubing or even of polythene.

Where the service pipe passes under the foundations of the house it should be threaded through lengths of drain pipe to protect it from possible damage as a result of settlement. The service pipe usually enters the house through the kitchen floor. Where this is of hollow boarded construction special precautions must be taken to protect the pipe from exposure to the icy draughts that may whistle through the underfloor space. An effective method of protection is to thread the pipe through the middle of a 150mm drain pipe and to pack it round with vermiculite chips or some other similar inorganic lagging material. From the point at which the service pipe enters the house it is often referred to as the ‘rising main’. In a modern home it is likely to be of half-hard temper copper tubing, though stainless steel or p.v.c. tubing may also be used.

Immediately above floor level the rising main should be provided with a stop-cock—the householder’s main stop-cock. Immediately above this should be a drain cock.

These two fittings permit the water supply to the house to be cut off and the entire length of the rising main drained when required.

In the past it was quite usual for all cold water services, including the bathroom cold taps and the w.c. flushing cistern, to be connected direct to the rising main. Today however, the regulations of most Water Authorities, and good plumbing practice, permit, at the most, four connections to this pipe.

The first of these is to the cold tap over the kitchen sink. This is the tap that supplies water for drinking and cooking purposes and it is essential, on health grounds, that it should be supplied direct from the main and not from a storage cistern. A second connection may be made to the rising main at about the same level as the branch supplying the kitchen sink. This is for a branch supply pipe to serve a garden or garage tap. Such a tap can be provided only with the permission of the Water Authority who will usually make an extra charge on the water rate for its installation and use.

Typically, a garden supply pipe is taken through an external wall and turned over into a wall-plate elbow. A bib-tap, preferably fitted with a hose connector, is screwed into the outlet of this elbow. It is important that a separate stop-cock should be inserted into a garden supply branch pipe of this kind. At the onset of winter the stop-cock can be closed without affecting the other household services. The supply pipe can then be drained and the garden tap left open to eliminate the risk of frost damage.

From the kitchen the rising main will pass upwards to supply, via a ball or float valve, the main cold water storage cistern. This will probably be situated in the roof space. In its journey to the roof space the rising main should preferably be fixed to an internal wall though, in a modern home with central heating and cavity wall infilling, this is less important as a frost precaution than it formerly was.

The fourth, and final, branch that may be taken from the rising main of a well-designed modern plumbing system is also taken from within the roof space. It is to the ball valve supplying the small feed and expansion tank of an indirect hot water system, possibly used in conjunction with a central heating installation.

All other cold water services should be supplied by means of distribution pipes taken from the cold water storage cistern. There will usually be at least two, possibly more, of these. They should connect to the storage cistern at a level about 2in above its base to reduce the risk of grit and detritus from the water main being drawn into the distribution pipes.

Where there is a cylinder storage hot water system a supply pipe at least 22mm and preferably 28mm in diameter must be taken from the cistern to connect to the cold supply tapping near to the base of the cylinder. Where the hot water system is a conventional indirect one a drain cock should be provided in this supply pipe near to the cylinder connection to enable the cylinder to be drained.

It is very important that no branch supply pipe to any other draw-off point should be taken from the pipe serving the hot water storage cylinder.

Another cold water distribution pipe-again, at least 22mm in diameter-is taken from the cold water storage cistern to provide bathroom cold water supplies. This is taken direct to the %in cold tap of the bath and 15mm branches are teed off it to supply the w.c. flushing cistern and the cold tap over the bathroom wash basin.

If an independent shower or a ‘through rim’ bidet are installed, separate 15mm cojd water distribution pipes must be taken, direct from the storage cistern, to supply them with cold water. The reasons why separate supplies must be taken to these fittings will be explained when their installation is considered.

It is obviously to advantage to be able to isolate individual distribution pipes without affecting the rest of the household water supply system. This can be done by fitting gate valves into the distribution pipes close to the storage cistern. Make sure that these are the right size for the particular pipe-line and that, when not in use, they are left fully open. A pipe is only as wide as its narrowest point! Alternatively each individual draw-off point can be isolated for servicing by fitting a small isolating stop-cock in its supply pipe just before connection to the tap or ball-valve concerned.

Stop-cocks and gate valves

The purpose of both stop-cocks and gate valves is to control the flow of water through water supply pipes. A screw-down stop-cock resembles in every way a conventional bib-tap set in a run of pipe. Turning the crutch or wheel head raises or lowers a washered valve or jumper onto a valve seating.

By far the commonest defect to which screw-down stopcocks are prone is that of jamming in position after long periods of disuse. A sudden emergency such as a burst pipe or leaking cold water storage cistern sends the householder hurrying to the main stop-cock, only to find that it is immovable. A jammed stop-cock can usually be freed after applying penetrating oil and attempting to turn it, perhaps over a period of several days. It is however far better to stop it from jamming. This can be done by opening and shutting it several times, about twice a year. Finally, open the stop-cock fully and then give a quarter-turn towards closure. This will not affect the water flow but will prevent jamming. Make sure that all the family know where the main stop-cock is and that turning it off should be the first course of action in practically any plumbing emergency.

Stop-cocks, like taps, may occasionally need rewashering. To do this the water supply to the stop-cock must first be cut off. With the main stop-cock this will mean seeking the assistance of the Water Authority. The headgear of the stop-cock is then unscrewed and removed, the small nut holding the washer in place on the valve removed and a new washer-of the right size-fitted.

Failure of the gland packing is a rather more common defect. It will make itself known by water dripping from the stop-cock spindle.This demands immediate attention. A constant drip onto a wooden floor-particularly in the badly ventilated situations in which stop-cocks are often situated-can be the prelude to dry rot.

It may be possible to stop the drip by giving the gland adjusting nut-the first nut through which the spindle of the stop-cock passes—half a turn or so in a clockwise direction. Eventually however all the adjustment will be taken up and it will be necessary to renew the gland packing. Turn the stopcock off-there is no need to cut off the water supply to it. Unscrew and remove the grub screw holding the crutch or wheel head in place and remove the head. Unscrew and remove the gland adjusting nut. Pick out the old gland packing with the point of a penknife blade and repack using household wool steeped in petroleum jelly. Caulk down hard. Reassemble the stop-cock and open it.

When fitting a new screw-down stop-cock make sure that it is fitted so that the arrow engraved on the stop-cock’s body points in the direction of the flow of water. If it is fitted the wrong way round water pressure will force the valve down onto its seating and it will remain permanently closed.

Gate-valves closely resemble stop-cocks in external appearance but, when screwed down, a metal plate or ‘gate’ closes the waterway. Screw-down stop-cocks are normally used in pipe-lines subject to mains pressure and gate valves in situations, such as in the distribution pipes from a cold water storage cistern, where the water pressure is low.

Isolating stop-cocks are small, unobtrusive control valves that can be fitted into a pipe-line at any point to isolate a particular tap or ball valve when required. They therefore permit tap washering or renewal with the absolute minimum of disruption to the remainder of the domestic water services. They are opened or closed by means of a screwdriver.

Drain cocks

A drain cock should be fitted at the lowest possible point on any pipe that cannot be drained from a tap-immediately above the main stop-cock, at the base of the cold water supply pipe to an indirect cylinder or to a direct cylinder heated by an immersion heater only, on the return pipe, beside the boiler, of a hot water or central heating system.

The drain cock is opened by turning, with a spanner, the square shank protruding from the body of the fitting. This unscrews a washered plug from a valve seating and allows the pipe to be drained. Drain cocks have a hose connector outlet to permit drainage to an external gully. Drain cock outlets may become blocked with grit and the products of corrosion. They should therefore be opened, with a bucket placed underneath them, from time to time, to make sure that they are still working properly. If, when a drain cock is opened, water fails to flow, probing with a piece of wire will usually clear the obstruction.