Surround it with sand, (not shingle) and ensure that it is at least 450mm below ground level (unless it is the main supply pipe for your house, in which case refer to the supply company: Some require it to be 750 or even 900 deep). If you are being REALLY careful, you might lay a strip of coloured plastic above it, a warning tape, so that anyone digging in the area knows to be careful.
Mike
Good point about an accessible filter. We built an outdoor test rig which used about two cubic metres of water each day. Our landlord installed the needful. He paid him a small fortune for his meter and about 80 metres of mains MDPE and its trenching. He didn't include a filter, some gravel got into the meter, it jammed the mechanism and we had exceptionally low water bills for four years.With light well excluded there shouldn't be a problem with things growing in and blocking the pipes, but you'll need good fine filtering at the entries to them to keep out muck from the rainwater source and from the pond. (I didn't on a 'water feature' some years ago and had fun cleaning out the result).