My bath taps are extremely hard for my kids to turn off. I know I need to replace the washers but I've resisted doing it as I can't seem to find a way to turn off the water except at the mains - The hot water continues to flow as does the cold from the tank in the loft. What are the sizes of washer I'm likely to need to do this? If I'm going to have to drain the hot and cold tanks I'd rather have what I need available without having to go out in the middle of it all. The taps are about 20 years old if that suggests anything.
Tanks