1 manhole approx. 325 x 420 mm in the front bottom; tanks were professionally cleaned and overhauled by the manufacturer in 2024; brand new residual drain valves (screwed on to reduce the outlet to DN 50 DIN 11851 (with butterfly valve)) and manhole seals were installed; walls curved outwards; small dents in the front bottom possible; Total height including end of plastic tube level indicator approx. 3,850 mm