What happens to diesel from a boat or marina tank?

In brief

Boat and marina tanks breathe damp air and sit unused for months, so water, diesel bug and phase separation are common. Once collected, collected diesel is tested, water and sediment are settled out, and the fuel is filtered. Call 07950 582635 or send an enquiry.

Testing diesel after collection

A sample in a clear jar shows water, haze and sediment; water-finding paste on a dipstick shows free water at the bottom of a tank. Laboratory tests measure flash point, density, water content and microbial contamination.

Diesel from a boat or marina tank: what to do first

Pump contaminated fuel into fuel-grade containers or a bowser on shore, never into the water, and keep spill kits to hand. Closed, labelled containers in a bunded store on land, away from the water's edge.

How City Fuel Services handles waste diesel

Every load of waste diesel is assessed before anything is booked. Tell us the quantity, the containers and any contamination; we confirm the terms, collect with a suitable vehicle, and take it to a permitted facility on a consignment note.

Terms used in this answer

Digital Waste Tracking: The government's online service for recording waste movements. Permitted sites receiving waste in England and Wales have had to use it since 1 October 2026.
Consignment note: The document that travels with hazardous waste from the producer to the receiving site. Each person in the chain completes and signs their part.

Key facts
Situation	From a boat or marina tank
Priority	Before the boat is next used: contaminated fuel is a common cause of engine failure on the water.
Fuel	Diesel
Also called	DERV (diesel engine road vehicle), road diesel, white diesel
Waste code	13 07 01* (fuel oil and diesel)