Amsterdam Schiphol Airport has drinking fountains at most if not all toilets[0]. There's been a short period recently apparently where they were getting replaced and so were unavailable.

The city of Amsterdam has 500 fountains or bottle filling stations[1]. The rest of the country has at least 2400 more[2].

[0]: https://www.wateratairports.com/topic/schiphol-airport-ams/ [1]: https://www.waternet.nl/service-en-contact/drinkwater/gratis... [2]: https://drinkwaterkaart.nl/waar-kan-ik-gratis-water-tappen/