Where was One Cut of the Dead filmed?

2017 Japanese film directed by Shinichiro Ueda

One Cut of the Dead (2017) was filmed in Mito and Ashiyama water purification plant, 2 places named in its Wikipedia article, in Japan. 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.

See them on the map → Wikipedia Source data

Places per Wikipedia's article

The Wikipedia article names 2 places. Each links to the sentence that says so.