When joining EU, Czech Republic had to raise 5x nitrate limits in drinking water. Mainly for pollution in germany. Now water for toddlers is not safe for some aquarium fish.
[1] http://www.eea.europa.eu/data-and-maps/indicators/nitrate-in...
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:1...
If so, it says under (19) that member states are free to set more stringent limits if they so please.
But some points:
- EU Shengen rules are pretty strictly enforced. EU even regulates "curvature of bananas". I can not imagine situation where Germany could not sell bottled water on Czech market.
- All formulation are talking about human health; "essential quality and health parameters" or "if human life is endangered". I do not think this applies to german bottled water. Czech springs (and bottled water) are pretty high quality, and our limits were very strict even compared to international standards.
- I mentioned it as a curiosity. Because communism caused lot of pollution in here. Back in 2000 it was a huge contrast to cross borders to Germany or Austria. It is surprising that we had stricter rules on water.