Work on fixed water and heating installations needs an autoriseret VVS-installatør (authorised plumbing contractor), or a firm that brings one. Ask which it is, and ask for that on the invoice (faktura). Authorisations are looked up at Sikkerhedsstyrelsen, sik.dk.
Viborg covers the old centre and places such as Karup. Many jobs are houses and rural properties. Distances in the municipality can be longer than the postcode suggests. The same 4 businesses as the Danish page: ABC-VVS ApS, Hald Ege VVS ApS, Sdr. Rind & Vinkel VVS Viborg Blikkenslageri, VVSmesteren v/Torben Boldrup Storgaard.