What size water line would you need if you're building a new home and need about 175' to reach from the meter to your home and you're considering plastic or copper and the soil is sandy with no rocks?

Water lines are sized by the number of fixtures, not the distance from the meter to the house. PVC pipe is cheaper and more flexible. Copper pipe will last longer, but costs a lot more. I would suggest using inch and a quarter Schedule 80 PVC pipe for the water line from the meter to the house. This will give you the volume you need. Schedule 80 fittings are a lot stronger than Schedule 40. The fittings are the weakest link when it comes to PVC pipe. Copper has a tendency to attract minerals from sand over time. This will cause electrolisis over time. This may take several years to develop. So, you can't go wrong either way, but remember, nothing lasts forever.

ANS 2 - I would suggest using 1 1/4 Municipal Poly pipe. This is commonly used in my area and is flexible, very strong and has no joints every 20 feet as PVC does. Easy to fit and VERY hardy.