Any idea why tap water goes stale overnight? We have great tap water here in Hungary. My only problem that it goes stale overnight sometimes in some glasses or sometimes even the 2L water boiler has this problem too. But microbes cannot resist 100°C or 20% vinegar, so I thought it might be rather a chemical compound what causes it. It is really hard to get rid of it. When I use boiling water or vinegar it does not remove it. When I use soap and water several times, it removes it most of the times, but only for a few days. The only working solution was not using the affected glass for a month. It is hard to descibe the taste, but it is something like how new Chinese clothes or paint thinner smell so it is sort of strong plastic taste. The longer I use a glass without washing it every day, the bigger the risk it develops this feature (2 days are enough for certain glasses, while others never develop it), so maybe microbes are producing it after all, but the compound is long lasting even if they die off. Any idea what causes it and more importantly how to get rid of it permanently without having to wash my glasses, boiler, water jug each day?
Exclude reasons one by one
Surface biological contamination: use two vessels, wipe the one of them with H2O2, hydrogen peroxide solution, leave another untreated. Check if time till smell appears is different by a few days. Bacterias can survive 20% vinegar and 100*C for a short time, some of them, if they are in a sleeping stage, it is not quite reliable method i would say.
Tap water biological contamination: use two vessels with water, add a few tablespoons H2O2 with water in one, and just water in other. Check if time till smell appears is different by a few days.
Tap water chemical contamination: buy some bottled water, use two vessels, one with tap water, another with bottled water. Check if it will be different in a few days.
Bulk material of the vessel releasing chemicals: leave water in different material vessels, one is glass, another one is your preferred one. Check if glass vessel has less smell adter a few days. Glass releases the least amount of chemicals into the water.
Dust accumulation: use two vessels, cover one and leave another one open, check if smell will appear faster in one.
Psychological factor: use two identical vessels, ask your friend to give you one or another, randomly, blindfold yourself, do a test 10 times, check if your score is above 8 correct guesses out of 10 tries.
After completing this tests you will narrow down your search significantly to give you some idea about what is going on.