I had the same problem with distilled water. It taste nasty, but when I added terramin clay to it and left it for a day or more it tasted better. I admit I've never drank osmosis water, but everything I have researched suggests that both reverse osmosis and distilled are the safest waters to drink with regard to avoiding pollutants. However because the water has been so purified, there are hardly any minerals in it making it aggressive in your body, pulling minerals from it. It probably explains why it taste so bad also. It's recommended to re-alkalise and re-mineralise the water to compensate for this - using lemon juice / or dark green leafy vegetable, or clay - see terramin, Sea Salt etc. Don't add more than a 1/4 tsp of Sea Salt or himalayan salt to 2 litres of water though otherwise that also taste horrible.