If you find that you have a metallic taste coming from your copper water pipes, then you may want to get rid of this by either taking out the copper pipes altogether, or by altering the water once it comes out of the tap. Water can be refrigerated to take some of the taste away. You can choose to use a water purification system which will take out the copper contained in the water, which will also benefit your health.
Step 1 - Chill Your Water
If you want to make your water taste less metallic, but don't want to do any serious work to your copper water pipes, and don't want to fit purification tubes, then you should just fill up a jug of water, and pop it into your fridge. Leave this to cool for a few hours, and then take it out and drink. You could also add ice to a fresh jug. You could improve the taste of the water by adding a little lemon to the water.
Step 2 - Purify the Water
Another alternative is to purify the water. You can do this by attaching a registered water purifier to your pipes, before it reaches the faucet. This will remove the bad taste, and improve water quality.