The tank is located inside a building or outhouse.
Oil spills could run into an open drain or loose manhole cover.
If the tank vent pipes cannot be seen when the tank is being filled, for example if the delivery tanker is parked too far away or it is filled using a remote fill.
It is located within 10 metres of coastal waters or inland fresh waters such as lakes or streams.
It is located within 50 metres of a drinking water source, for example wells, boreholes or springs.
Oils spills could run over hard ground and reach coastal waters, inland fresh waters or a drinking water source.
It is in the inner zone of a groundwater source protection zone 1.