Even so, there are official references. The Portuguese National Health Service (SNS) recommends drinking around 1.5 to 2 litres of water a day, depending on the person and the situation. The European Food Safety Authority sets the reference intake at 2 litres a day for women and 2.5 litres for men. This figure includes all the water from both drinks and food. It tends to increase on hot days<\/a> or during greater physical effort.<\/p>\n\n\n\n More important than memorising a number is getting into the habit of drinking water throughout the day, in small amounts. Avoid trying to make up for it all at once in the late afternoon. Your body absorbs water better when it comes in regular doses. This also prevents the bloated feeling that comes from drinking large volumes in a short time.<\/p>\n\n\n\n For this reason, rather than following a fixed rule, it is more useful to pay attention to the signals your own body sends. We cover this topic next.<\/p>\n\n\n\n Thirst is usually seen as the main sign that your body needs water, but it is actually a late signal. Mild dehydration often affects the body before thirst appears. Unexplained tiredness, headaches, difficulty concentrating and irritability may be linked to a lack of water. They are not always down to lack of sleep or stress, as people often assume.<\/p>\n\n\n\n Other less obvious signs include drier skin than usual, chapped lips and darker urine. On their own, none of these signs is a cause for concern. Taken together, however, they deserve attention, especially on hotter days or during greater physical effort.<\/p>\n\n\n\n Beyond the amount you drink, there is a question that comes up more and more often: does the quality of your water make a difference? The answer is yes. This is not so much about how much water you drink, but about the experience and confidence that come with drinking it.<\/p>\n\n\n\n In Portugal, tap water undergoes rigorous treatment processes. According to the Portuguese Water and Waste Services Regulation Authority (ERSAR), the national safe water indicator has remained above 98%. This confirms the high quality of the water supplied to the tap. Even so, this water may retain tastes and odours from the chlorine used for disinfection. Its hardness, that is, its mineral concentration, can also vary from region to region.<\/p>\n\n\n\nWhat affects how much water each person needs<\/h2>\n\n\n\n
\n
Signs of dehydration that go unnoticed<\/h2>\n\n\n\n
![\"Glass](\"https:\/\/filtrarte.com\/wp-content\/uploads\/2026\/10\/agua-filtrada-copo-e-jarro-1024x687.jpg\")
<\/figure>\n\n\n\nFiltered water and tap water: what changes in practice<\/h2>\n\n\n\n
![\"Drops](\"https:\/\/filtrarte.com\/wp-content\/uploads\/2026\/10\/agua-pele-e-hidratacao-1024x687.jpg\")
<\/figure>\n\n\n\n