The most common bacteria found in drinking water is coliform (e-coli), which is from human (or animal) waste. Any bacteria usually comes from the water source (Lake, well, etc), but can also come from seepage into the water pipes or if a pipe ruptured and was repaired / replaced. When pipes are repaired / replaced, the utility MUST Super Chlorinate the pipe to kill any bacteria that may be present. Chlorine is the most effective way to do this. Most people can not test for bacteria by themselves, as chemicals are needed as well as pads, a syphoning machine, an oven (not your ordinary home one) and a desiccator to dry the pads. Copper usually found in water naturally, but in very, very low levels. Any significant amounts present would be due to the piping in your home (Homes built after 1970 or so shouldn't have a problem with this). Lead is also present in low levels naturally in water, and usually just in well water, and is not usually (very rare) at levels enough to cause any health problems unless you drink something like 100 glasses of water every day of your life, and even then the risk is very, very low. Your water provider tests for all of these (Bacteria weekly....lead and copper monthly from designated locations in the distribution system that is representive of the whole system). The source water is tested weekly for bacteria and copper, and daily for iron. If there is going to be any problem with these, this is where any problem would would occur. If there is a problem with iron, they can a chemicals to the water to help lower this (Not a common occurance). If ANY (more than 0) bacteria is found in the water at any location, that location is tested the next day (when results were obtained), and if any ae present at that time, by law the water provider MUST issue a "boil water" order. The water is then tested daily until the problem is cleared, and they must keep testing for another week after that to ensure that the problem is solved. If you want to know if any of these are in your home drinking water, all you need to do is call your water provider and they will come to your house and specifically test for these and give you the results the next day. All impurities found in water has a MCL (Maximum Contaminate Level), and any test done that exceeds these limits must be dealt with immediately.
