Tank Abandonment In Place
OAR 340-177-0100(2)(b) authorizes abandonment when removal would damage permanent structures · Controlled low-strength material is the preferred fill · Decommissioning Report still required
When a buried tank sits beneath a driveway, garage slab, addition, or mature retaining wall, OAR 340-177 lets us decommission by abandonment. We pump, clean to vapor-free, fill with flowable inert material, document, and close.
Quote this service
Tank size, depth, access, contamination risk. Site survey is free.
What this service covers
Some Eugene-area tanks cannot be removed without doing more damage to the property than the original installation ever caused. A 1962 buried tank in the Friendly neighborhood that was paved over with a concrete driveway in 1981 is a candidate. So is a College Hill split-level where a 1970s den addition was poured directly over the tank shell. Oregon DEQ recognizes this. OAR 340-177-0100(2)(b) explicitly authorizes decommissioning by abandonment in place when removal would damage permanent structures, mature landscaping, or load-bearing surfaces.
The work is regulated identically to a removal, just with one different middle step. The tank is located, pumped to dry, cleaned to vapor-free, and either cut open at the top to vent or, more commonly, fully filled with controlled low-strength material, a flowable cementitious slurry that self-levels, eliminates internal voids, and is what Lane County lenders and title companies prefer to see called out by name in the report. Soil samples are still pulled from accessible sides, the report is still filed at Eugene DEQ, and DEQ still issues a closeout letter.
The honest framing on cost: abandonment runs roughly the same as a removal because the cleaning, sampling, lab work, and reporting are identical. What you save with abandonment is not labor; it is the structural rebuild you would otherwise be paying for on top of the contractor bill.
How we run this service
Driveways, foundations, and additions stay intact
No saw-cutting load-bearing slabs, no breaking back into a foundation wall, no removing a deck or addition that has been there longer than most of the neighbors.
Same DEQ closeout as a removal
The Decommissioning Report submitted to the Eugene DEQ office documents the abandonment work, the soil sample results, and the inert fill. Lenders treat the closeout letter the same way they treat a removal closeout.
Controlled low-strength material fill, not sand
Self-leveling cement slurry is the modern preferred fill. We use sand or pea gravel only when slurry access is genuinely impossible, and when we do, we explain why in the report.
Documented justification
The report explains exactly why removal was not feasible at this property. That documentation is what allows DEQ to accept the abandonment instead of requiring excavation later.
Specific situations we handle
Under-driveway abandonment
Saw-cut a small access window, pump and clean through it, fill with slurry, patch the slab.
Under-addition abandonment
When a 1970s-80s room addition or attached garage sits over the tank, we work through fill and vent pipes plus a single keyhole excavation rather than removing the structure.
Re-decommissioning of pre-1990 informal closures
Historic backhoe-and-sand closures are not recognized under modern rules. We document under OAR 340-177 so the file closes properly at the next transaction.
CLSM (controlled low-strength material) flowable fill
The preferred fill: self-leveling cement slurry that eliminates internal voids and is the option most lenders ask to see in the report.
Pea gravel or sand fill (when slurry access is impossible)
Non-preferred but sometimes necessary; the report explains the reasoning so DEQ accepts it.
Lender and title company communication
Abandonment files draw the most underwriter questions of any closeout. We speak directly to lenders or title officers when the report needs explaining.
Who this service fits
Abandonment is the right path when:
- i.A concrete driveway, parking pad, or carport was poured over the tank in a later renovation and is now load-bearing access to the home.
- j.A room addition, attached garage, or deck was built directly on top of the tank, common on Eugene 1970s-80s remodels in Cal Young, Harlow, and the older South Hills.
- k.Mature trees, retaining walls, or significant landscape investment would have to be removed to reach the tank (South Hills properties especially).
- l.The tank straddles a property line and the neighbor will not consent to access from their side.
- m.A pre-1990 abandonment was performed informally (sand fill, no DEQ paperwork) and a current sale or refinance requires re-decommissioning under OAR 340-177.
How a job runs, start to finish
Survey and feasibility check
A short on-site visit confirms abandonment is the right call. Sometimes a smaller excavator or a single saw-cut access window makes removal cheaper than expected. The decision and its justification go in the file.
Permit and DEQ notice
Eugene, Springfield, or Lane County permit pulled. 72-hour DEQ Notice of Intent filed, identifying abandonment as the method and naming the fill material.
Pump, clean, fill
Tank is pumped, cleaned to NFPA 326 vapor-free, and filled through the existing fill pipe with controlled low-strength material. Top vented to release air during fill. The shell is now structurally inert.
Sample and report
Soil samples pulled from accessible excavation. Decommissioning Report assembled with photos, fill manifest, and lab results, then filed with DEQ within 60 days.
What this service includes
An abandonment in place under OAR 340-177-0100(2)(b) includes the same locate, permit, and 72-hour Notice of Intent steps as a removal, plus tank pumping to dry, NFPA 326 vapor-free cleaning, controlled low-strength material (CLSM) flowable slurry fill through the existing fill pipe and a vented tap, soil sampling from accessible sides of the excavation, and the Decommissioning Report filed at the Eugene DEQ office within 60 days. Re-decommissioning of pre-1990 informal closures (sand fill, no DEQ paperwork) uses the same workflow, since those historic closures do not satisfy current OAR 340-177 standards. Lender and title-officer communication about the abandonment paperwork is included, because abandonment files draw the most underwriter questions of any closeout.
Underground Oil Tank Removal
Excavate, decommission, and document buried heating oil tanks across Eugene-Springfield under the Oregon DEQ HOT program. Closes with an ORELAP-tested soil sample panel and a Decommissioning Report filed at the Eugene DEQ office.
View service →Tank Abandonment In Place: Common questions
My addition was poured in 1985 over the original tank. Is abandonment my only option?+
Practically, yes. Reaching a tank under a 40-year-old foundation slab without compromising it is rarely worth the cost of the structural rebuild. Abandonment in place under OAR 340-177-0100(2)(b) is the regulatory path designed for this situation: pump, clean, fill the shell with controlled low-strength material, sample wherever access permits, and file the closeout.
Will a Eugene buyer accept an abandoned tank in the property file?+
In most Lane County transactions, yes, provided the Decommissioning Report shows soil samples below DEQ Risk-Based Concentrations and the fill material and method are documented. A small number of buyers (typically out-of-state cash buyers without a lender at the table) will still ask for a removal. That is a negotiation, not a regulatory requirement.
Why does abandonment cost about the same as removal?+
Because the work that drives the bill (locating, cleaning to NFPA 326 vapor-free, soil sampling, lab fees, report writing, and DEQ filing) happens identically in both paths. What you save with abandonment is the cost of demolishing and rebuilding the structure on top of the tank, not the contractor's labor.
Ready to talk about your specific tank?
Free site survey. Fixed-price quote. Decommissioning Report filed at the Eugene DEQ office.