Where was Waterloo Road filmed?
British television drama series
Waterloo Road (2006–) was filmed in Greenock, Swinton and St Ambrose Barlow RC High School, 3 places named in its Wikipedia article, in the United Kingdom. Wikidata records no filming location for it at all, so the article is the only recorded source. Each place says where its claim comes from.
Places per Wikipedia's article
The Wikipedia article names 3 places. Each links to the sentence that says so.

