|Typical roof tank ballvalve, part2 type|
Ball valves are found in roof tanks and WC cisterns. It is generally as quick and easy to change a roof tank ball valve as it is to re-washer it. The older “part 1” or BS1212 type ball valve should be replaced with “part 2” type ball valve readily available from plumber's merchants.
Ball valves found in WC cisterns are essentially the same as ball valves in roof tanks, although in low level and close-coupled WC suites they are often of the bottom entry type. These are more difficult to replace so unless they are in poor condition it is probably best to re-washer.
There are many different plastic float valves found in modern WC cisterns, often requiring specific washer. Sometimes it's easier just to replace the whole valve. This may not be without it's problems, sometimes the new valve will not fit within the cistern very well with the float touching the side of the cistern, the threaded shank not he same length and so on.
If you leave your house empty for more than a few days, roof tanks and WC cisterns can start to overflow so it’s worth thinking about turning the water off.