Until the 1970ies central heating systems didn't really catch here, so wall mount gas water heaters (usually 5 or 10l on-demand types, I once posted a pic of a 5l type) are still pretty common. I think replacements are still readily available.
I looked up www.baumax.at,
here's the facts about electric storage heaters.
120l tank, 2000W, 230V, stainless steel tank,6 bar max. pressure, 119 Euro.
5l open system 39,99 Euro.