UK towable bowser regulations are variable according to usage and bowser type. In addition to this, the ADR do not recognise the term bowser, making regulation sightly more difficult to follow for many bowser users. If a bowser is called a wheeled trailer fitted with a tank, the following regulations generally apply;
Diesel and gas oil
The tank must not be “permanently fixed to a motor vehicle or trailer”.
The tank’s maximum capacity must be below 3000 litres.
The tank must be designed for ‘mechanical handling’.