Start With What Is Known
A fill pipe in a driveway, an old cover or a reference in property papers may be the only visible sign of a buried oil store. Tell us what you have found and whether the tank is still connected. Do not open a concealed chamber or attempt to enter it.
Old drawings, invoices and delivery records can help establish capacity and previous contents. Unknowns should stay visible in the enquiry rather than being replaced by guesses. A tank beneath a drive needs a different investigation from a visible above-ground tank with soil piled around it.
Removal Or Leaving The Tank In Place
Excavation can allow the tank to be taken away and surrounding ground examined. It also needs space, safe excavation and a plan for lifting and reinstatement. Proximity to buildings and buried services can limit what is practical.
Leaving a prepared tank in place may be considered where removal is impractical. Appropriate filling is part of a specialist decommissioning design, not a shortcut around cleaning. Environment Agency guidance favours removing tanks and pipework unlikely to be reused, with site-specific assessment where that cannot be done.
The Ground Needs Its Own Assessment
Removing or filling a tank does not resolve oil that has already escaped. A surface that looks clean cannot establish the condition of soil below it. Mention any historic smell, unexplained loss of fuel or earlier leak report before the method is selected.
An environmental specialist may need to plan sampling and interpret the findings. Water sources, drains, ditches and the future use of the land are relevant. Any remediation, additional testing and disposal of excavated material should be identified as a separate element of the programme.
Plan Access Above And Below Ground
The contractor needs to understand the excavation footprint and the route for machinery, recovered liquids and the tank itself. Photographs should show the cover or visible fittings, nearby walls, surface finishes and the access from the road. Add any known depth information from reliable records.
Underground electricity, water, drainage and other services need identification before digging, following the approach in HSE underground-services guidance. Tell us about private supplies and septic systems as well as utility connections. No one should assume that an old drawing proves the exact position or that an area beside a tank is clear.
Fuel, Residues And Safe Preparation
A disused buried tank may still contain fuel, water and sludge. These contents need assessment, recovery and appropriate handling before removal or filling can proceed. The preparation method must address the atmosphere and the planned work rather than relying on how long the tank has been unused.
If the tank is still feeding a building, agree the replacement supply and interruption first. A move to an above-ground installation may form part of the project, but it needs its own siting, support and connection design. See our installation guide for those decisions.
Compare Costs And Future Land Use
Depth, capacity, contents, machinery access and the surface above the tank all affect cost. Excavation beside a structure can need engineering input. Reinstating a lawn, paved drive or working yard involves different materials and handover expectations.
Explain whether an extension, foundation or landscaping scheme is planned. A filled tank is not automatically a suitable foundation or proof that the ground is ready to build on. The designer of future works needs the retained tank information and any investigation reports before relying on the site.
Keep A Permanent Property Record
Record the tank location, estimated or confirmed capacity, former contents, date and method of decommissioning. Keep the contractor's report and the relevant waste records. If a tank remains, retain details of the filling material and distinguish that clearly from physical removal.
Add photographs, any sampling reports and drawings showing retained pipework. For an enquiry, send the postcode, all available records and your intended use of the land. State whether there is an insurer, surveyor or builder already involved so the investigation can answer the right questions.
Underground Tanks Questions
Does Filling An Underground Tank Remove Pollution?
Filling an underground tank does not clean contaminated ground around it. Residual contents and the tank itself need treatment, while any escaped oil needs a separate assessment. Investigation may be required before the final decommissioning method is agreed, particularly where there are water sources nearby or building work is planned.
What If I Do Not Know The Tank Size?
An unknown underground tank size should be stated as unknown in the enquiry. Send any plans, delivery information and photographs of visible covers or fittings without opening them. An initial assessment can establish what further investigation is needed before a reliable method, waste allowance and quotation can be prepared.