Before World War II, companies that installed plumbing and sewers in Lviv (Lwów/Lemberg) attached plates on building where such services were provided. A few of these plates, which state in Polish that “wodociąg w tym domu” (water supply in this house) was installed by such and such company, can still be found in Lviv, though, as usual, some of the remaining ones have been painted or plastered over.

A collection of “wodociąg” signs in the courtyard of Kupol restaurant (image taken many years ago):

In this photograph taken in 1912 Józef Kościesza-Jaworski of a portal on Krakowska Street, we can see such a sign to the left of the door:

It reads: “Wodociągi w tym domu urządziła firma Bracia Mund Sykstuska 23 telefon 605” (The water supply in this house was installed by the Mund Brothers company Sykstuska 23 telefon 605)

Here is a close up of the same type sign that we can see in Kościesza-Jaworski’s photo. This sign is not in its original location, just used as decoration: