Back in California, if you were a water customer, you had a right to post a complaint about the water. No matter what it was, if you thought the water tasted like paint, they tested it; if you thought the water tasted like farts, they tested it; no questions asked. Taiwan offers the same service, with a very similar laboratory. Some time ago engerim
spent a small fortune exporting local drinking water samples to Europe, only to find out what the locals had already determined: nothing was doing. If you think you are smelling/tasting the lingering remnants of a joint compound from the piping, you are not going to win this case with laboratory tests*.
*What yo are experiencing is 'post construction disruption'. Legally speaking, there is almost nothing that can be done, and even if there was, we're talking NT$100,000 just to get started on something that *might* be real, but probably isn't.
To address your displeasure with the water department: it's not their problem! This is the result of an in-house construction issue that has nothing to do with city plumbing. YOUR building has caused this supposed contamination, not the city of Taipei, so lay off them.
If you really want to bring pressure to this situation, threaten your landlord. It's your choice how,but that man is the only one who is going to react (or solve) to your water problem. But, before you rattle too many sabers, remember you are only a measly foreigner; a stranger in a strange land. So, be prepared to battle properly, and accept appropriate consequences if applicable.
If the horrible water smell you detect is actually just a result of joint sealer, than it will be gone very soon. Plumbers, whether from America, Europe, or Asia, use roughly the same stuff to seal plastic pipes. Chances are good that whatever it is that has aroused your situation will be gone soon.
Don't, by any means. create a crazy foreigner episode base on your over-sensitive nose, because there are already enough crazy transplant town criers disenfranchising my people in this city.
Peace out Cub Scout!