Belgium

Brussels tap water meets EU standards and is safe to drink — you can drink from the tap and use it for brushing teeth. If you are staying in a very old building with antique plumbing, consider using a simple filter or bottled water as a precaution.

Antwerp's tap water is treated to EU standards and is safe to drink; you can ask for 'kraanwater' in restaurants. If you prefer softer-tasting water, buy bottled water, but it's not necessary for health safety.