Dead leg - Stop tap and drain off valve needed?

[gentlepersuader]

I am teeing off my below ground water supply pipe (25mm) to run a supply into the garage which is separate from the property and will eventually be converted to an annex.

The run is about 5 meters and will be unused for weeks at a time. My thought was to install a boundary box, stop tap and drain off valve to avoid stagnant water when not in use.

There are no videos on YouTube and no obvious components online which makes me wonder if I'm missing something. Can anyone advise if this is necessary and what parts I need (boundary boxes seem too small)?

Thanks!

 

[denso13]

Just run water through it for 5 minutes every few weeks.

 

[gentlepersuader]

Thanks Denso. I did wonder if that's the simple solution. The reality is that I would probably forget to isolate and drain it anyway, just trying to do it "properly".