Legal requirements for a Electric Water Heater maintenance in Brussels Region

I know Gas Water heaters need to be maintained once in two years by doing an 'entretien complete' .

I see a Electric water heater is used for shower and bath in an apartment I intend to buy. It is probably around 50 to 100 litre capacity, installed on the mezzanine floor in an attic apartment (on second floor), installed just behind the toilet. Literally a 1 meter  by 50 com electric boiler is sealed behind walls, only visible through an access door of 30 by 30 cm. I do not think any access is possible even for maintenance unless the tiles/bathroom wall are broke open.

Enclosing pictures which shows probably installation doesn't confirm to proper technical standards/Requirements.

Are there any requirements by law  for electric water heaters to do any routine checks in Brussels capital region?

Thanks in advance