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This document explains why some buried oil tanks or septic tanks float up out of the ground, what that event means to the property owner, and how to prevent oil tank or septic tank flotation. © Copyright 2010 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

WHY OIL TANKS or SEPTIC TANKS FLOAT up out of the ground during heavy rains or flooding

The photograph at the top of this page and this close up show an old abandoned oil tank which has burst up out of its grave in a thicket along a creek in New York. Recent rains and area flooding brought water level above the top of the ground in which this empty and buried tank had rested for decades.

As water levels rose the buoyancy of the empty tank caused it to lift right out of its burial spot where it had been hidden. A prior owner had even unscrewed the tank fill and vent valves so that there was no evidence of its presence along this creek.

Oil is lighter than water to begin with, but an oil tank or septic tank which is in use and full is unlikely to rise out of flooded ground even so. But an empty steel, plastic, or fiberglass tank used for oil storage, such as heating oil, or for a septic tank, is very buoyant. Even a modest increase in ground water can be enough to push the tank up through the ground.

When a buried oil tank or septic tank is lifted by rising water or flooding, any piping connections to the building it serves are likely to be severed, leading to an oil spill or a sewage spill.

The tank shown in these photos should not have been installed by a creek in the first place, which may explain why it was later emptied and "abandoned" in place. Had the tank been properly abandoned it would have been cut open, cleaned, and filled with clean sand. The fill should have prevented the buried oil tank from rising to the surface despite later rising ground water or floodwaters.

A buried oil tank or a buried steel, plastic, or fiberglass septic tank can be prevented from dislocation caused by rising water or flooding if it is either kept full or is physically anchored to the site using cables or other means.

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Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

OIL TANK HOME
  HOME BUYERS GUIDE TO OIL TANKS
ABANDONING OIL TANKS
ABOVE GROUND OIL TANK INSPECTIONS
BURIED OIL TANK ADVICE
BURIED OIL TANKS, FINDING
FLOATING UP OIL STORAGE or SEPTIC TANKS
FUEL OIL TYPES & CHARACTERISTICS
HEATING OIL EXPOSURE HAZARDS, LIMITS
HEATING OIL SHELF LIFE
OIL TANK ABANDONING PROCEDURE
PLUMBING TOPICS
SEPTIC SYSTEMS HOME
SEPTIC TANK INSPECTION PROCEDURE

More Information on Building Diagnostic Inspections and Repairs

• Oil Tanks - The Oil Storage Tank Information Website: Buried or Above Ground Oil Tank Inspection, Testing, Cleanup, Abandonment of Oil Tanks
• Abandon a Buried Oil Tank, How To - Abandoning Commercial Underground Tanks, Russ Brauksieck, ASHI Tech. Journal, Vol.3 No.1 Spring 1993, P. 40-41 [Reprint]
• Above Ground Oil Tanks: Visual Inspection of Oil Storage Tanks for evidence of leaks, damage, improper piping - photos and text
• Above Ground Oil Tanks Checklist, an Oil Company's advice
• Above Ground Tanks UL Standards, UL Tank Listing Standards, guidance for home owners, buyers, and inspectors
• Buried Oil Tanks - Finding How to Find Buried Oil Tanks and "Nearly Hidden" and Leaky Oil Tanks - photos and text.
• Buried Fuel tank - Advice - Buried FUEL Tank - GAS or OIL advice for home buyers, inspection report language
• Environmental Issues & Regulations for Oil Tanks, Registration, Abandonment, Leak Reporting
• Home Inspection Report Language Library: Buried Oil Tanks, Basic home buyer advice - home inspection report language suggestions
• Home Inspection Report Language Library: Visible Defects in Oil Tank Installations, Tanks, and Heating Oil Piping
• Home Inspection Report Language Library: Gas Fuel Piping or Tank Faults Basic advice - home inspection report language suggestions
• Home Inspection Report Language Library: Oil Tanks text file list © Oil and Other Storage Tank Leaks, Testing, Abandonment, Inspection - UST home inspection report language files - Reference List
• Indoor Environment Website Indoor Building Environmental Hazard Detection, Testing, Repair, & Prevention - Main Web Page
• Leaky Heating Oil Tanks - Advice for Home Owners or Buyers: caused of leaks in oil tanks, oil tank testing alternatives, what to do about leaky tanks: D.J. Friedman, ASHI Tech. Journal, Vol.2 No.1, Winter, 1992 p. 42-43 Illus
• Leak or Failure Rates for Home Heating Oil Tanks
• Legal Issues Regarding Buried Oil Storage Tanks K.S. Rea, Attorney, summary from ASHI Chapter Seminar.
• Primer on Petroleum Bulk Storage Tanks & Petroleum Contamination of Property Paul H. Ciminello, ASHI Tech. Journal, Vol.3 No.1 Spring 1993, p 35-39
• Petroleum Bulk Storage J. Sibblies, NY State DEC, Advice to Home Owners and Home Inspectors about Oil Storage Tanks - summary from ASHI Chapter Seminar.
• Septic Tank inspection, testing, diagnosis, repair
• OIL TANK FAILURE CAUSES - Oil Tank Failure Causes - oil tank leaks are caused by corrosion, damage, soil conditions, other factors
• TANK FAILURE RATES - Oil Tank Failure Rates - Oil Tank Leak Probability as a Function of Tank Age, Location, Condition, Soil Conditions and Other Factors
• OIL TANK TESTING - - How Oil Tanks are Tested for Evidence Leaks, of Current or Previous Oil Spills
• Web Link Exchange: Contact Us to list your website or contact information for oil tank testing, tank corrosion research, oil industry experts

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