Sanitary dump stations

Touring Valdres with a motorhome, you can find public sanitary dump stations in
Etnedal at Bruflat renseanlegg
Sør-Aurdal at Circle K in Bagn

In addition, the following campgrounds welcome others than their own guests against a fee:
Nord-Aurdal: Fagernes Camping, Aurdal Fjordcamping
Øystre Slidre: Beitostølen Camping
Vang: Bøflaten Camping

You can find an overview over dump stations in Innlandet Fylke on https://bobilplassen.no/tommestasjoner-i-oppland/