Question:
i recently plumbed water to my garage in order to brew there instead of my kitchen. i used black plastic pipe and ran it through an aqua pure water filter with the filter cartridge for dirt; not the carbon filter cartridges. the water tastes terrible to me. granted that i could have installed the filter wrong, but could the black plastic be the cause of the horrible taste? or do i just need to run a little water through the pipes to clear them out? any ideas?

Answer: There is more than one type of plastic pipe that is available in black.

Rigid black cellular core ABS pipe is used for drain/waste/vent use only. You also won't usually find in sizes under about 1.5" or so.

Flexible black polyethylene pipe is indeed used for potable water (cold). It is frequently used for the feed from submersible well pumps.

I believe you can also find PEX (cross linked polyethylene) pipe (tubing) in black, although red and blue are the most common.

Either way any new plumbing you do should be flushed well after installation. Even with flushing, new plastic pipe may impart a taste for a while. If you simply run the water (down the drain) for long enough to purge the plastic line of the water that has been standing in it you should get acceptable water since it will not had much time in contact with the plastic. A carbon type filter cartridge wouldn't hurt either.