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.
Randers has a centre and housing areas in Randers SV and SØ. Many jobs are houses. A drive out of town is common. The same 4 businesses as the Danish page: ASSENTOFT SMEDE-OG MASKINFORRETNING A/S, GAS- OG VANDMESTEREN ApS, Nøddelund Smedie og VVS, Randers VVS ApS.