One risk with having two separate water pipework systems in a building, where one set of pipes carries Drinking Water supplied from the mains and the other set carries Rain Water, is that it’s important to ensure the right pipe is connected to the right appliances – especially when new connections are being added some time after the original pipework was installed. Accidentally connecting to the wrong pipe won’t be obvious since both pipes carry cold water, but Rain Water is not safe to drink (and must not be allowed into the water supply network).

In the Outbuildings (as opposed to the House) it helps that the pipework is exposed so it’s not too difficult to trace the pipes, but the regulations rightly specify that the rainwater pipework needs to be clearly labelled at suitable intervals.

It seemed sensible to label both sets of pipes, for extra clarity, and to follow the BS1710:2014 guidance for the label colour scheme. This uses Green as the background colour (to indicate a Water pipe) then various other coloured band(s) to indicate the type of water and the source. RM Labels offer a nice range of pipe labels and valve tags and I settled on:

• For the Drinking Water pipes, their Drinking Water Pipe Marker PMW32a which has a Blue band, indicating “Potable water derived from the public water supply”
• For the Rain Water pipes, their Rain Water Pipe Marker PMW59a which has a Grey band (to indicate a source other than the public water supply) and a Black stripe (to indicate the water is non-potable).

While it is of course necessary to follow the label colour standards and professional plumbers should be familiar with the colour codes, I’m not sure who else would know what the Grey, Black and Blue bands mean – but the text makes the pipe contents clear too.

One minor problem is that these labels don’t stick very well to polythene pipe insulation – especially in cold and damp conditions – so I opted to over-wrap the labels with the sort of clear sticky film intended for wrapping paperback textbooks (visible as a shiny band in the photo). That film is cut long enough to wrap over onto itself, which should help it stay in place.

(An alternative would have been to use slightly different labels that are supplied on a roll and which wrap all around the pipe by themselves, e.g. Drinking Water Pipe Banding for Potable Water from Public Water Supply – Self-adhesive – PB001PWPWS and its equivalent for Rain Water.)