Water supply to outhouse

[Tex_1]

Hi, im after some advice on how to supply water to a washing machine in our out house. There is a outside tap near by can I T off that or do I need to come off the mains supply with mdpe and use a stopcock where it enters the outhouse etc.
Any help is appreciated

 

[Best]

About 2 feet down minimum will be reasonable depth from freezing and avoiding getting easily hit with a spade, but not to regs.
Probably sleeved pipe would help