A cuboidal water tank is 6 m long, 5 m wide and 4.5 m deep.

Given data:

Length (l) = 6 m

Breadth (b) = 5 m

Height (h) = 4.5 m

Volume of the tank = l * b * h

= 6 * 5 * 4.5

$=135 \mathrm{~m}^{3}$

It is given that,

$1 \mathrm{~m}^{3}=1000$ liters

Therefore, $135 \mathrm{~m}^{3}=(135 * 1000)$ liters

= 135000 liters

The tank can hold 1, 35, 000 liters of water.