Well, water usage is usually metered in cubic meters. A thousand m^3 per year sounds much less than a million litres.
Volumes are in general very unintuitive to people due to the cubic scaling. It’s further confused by the fact that the widely used decilitre, centilitre, and millilitre do scale linearly, unlike cubic metres. So 1 l = 1 dm^3 but 1 dl = 100 cm^3…