What could cause tap water that was previously potable to suddenly taste bad? If there is no notice from the supplier that it is tainted, would it be OK to drink the water?
You can check the answer of the people under the question at Quora “all of a sudden coffee tastes bad“
My first thought would be some form of contamination. Is it just the taste? Is there any discolouration of your water? Any noticeable smell or odour to the water? If the answer is no, has the water not been run for a while, have you been away? If yes then it could be just stale water in your supply pipe, the water main circulates fresh water 24/7 but the water from the street main to your home just sits there until you turn on your taps. If in the UK, you can always ring your water supply company and describe your problem. If they cannot sort it over the phone, they can send a water quality technician to collect samples for analysis.
P. S. If it is a chlorine taste, try this, fill a clean, empty bottle with tap water an put into a fridge overnight, you will be pleasantly surprised at the result.
Call your town council to verify the problem. Or send a sample to the lab yourself. Ask your neighbors whether they have the same problem? Ask a water sample from them as well. Meanwhile, please don’t drink the water even if you are thirsty, use store bought bottled water.
Thank you.
What sort of bad tasting?
I once had a bacteria colony in my water heater. A shock treatment with bleach fixed it.
But the nature of the problem may vary.
To paraphrase Tolstoy, all good water is alike. Every foul water is unique in its odor
If the water tastes bad it could be a problem with the water itself or with the pipes in your building. Call your water provider and tell them that the water in your place started to taste bad, they will check the state of thing up to your building. If they report the water is OK, talk to the owner of the building because there is a malfunction somewhere in the pipes of the building. Meanwhile do not drink that water and do not use it to brush your teeth or to cook with.