There is probably no topic more discussed by holiday makers than whether the tap water is safe to drink. Most of the tap water, in the towns, comes from wells or water treatment plants and it is all treated, just like in the UK, to make it safe to drink. In the early days of tourism on the Coast this wasn't always the case and it is, presumably, from these times that the rumours grew about the dangers of drinking the water. Spain is part of the E.U. and, as such has to comply with the same rules and regulations as the rest of the community.
One point that we would make is that the water does have a different mineral content and some people claim that it can upset them until they get used to it. If you are concerned about this then you might be wise to stick to bottled water for drinking. However there is no worry about using tap water for brushing your teeth or having ice cubes in your drinks etc.
With regards to drinking water it is worth noting that all bars, by law, are obliged to provide you with a glass of water at no charge - this only applies to tap water and some non-Spanish owned bars may not be aware of this regulation.