Risks/Issues :: Residential & Farm Tanks
»Risks/Issues
:: Commercial & Industrial Tanks
This page attempts to answer the question: Why should I have
my petroleum underground storage tank inspected? Well, there
are many reasons to have your tank checked, but the most compelling
reason is that a leaking tank may cause serious damage to
your property or neighboring properties if it is not properly
addressed, and financial
assistance is currently available to address it if there
is a problem. If a problem is discovered in the future, the
owner will be liable for cleanups and damages, but financial
assistance may not be available. Besides, we make the process
simple for you; we do all the work.
What follows are important issues surrounding petroleum storage
tanks, and at the bottom of the page we have included a brief
discussion of the science behind leaking tanks and the migration
of the contaminants.
BOCA National Fire Prevention Code and the Uniform Statewide
Building Code
The BOCA National Fire Prevention Code and the Uniform Statewide
Building Code state that (paraphrase) petroleum storage tanks
that are abandoned for more than one year shall be emptied
of their contents and removed from the premises. (Most localities
will allow the tank to be filled with an inert solid if removal
is obstructed). It is left up to the localities to enforce
this code and many fail to enforce it on residential properties.
State Water Control Law
Article 11 of State Water Control Law requires that discharges
(leaks) from home heating oil tanks and farm motor fuel tanks
be reported to the Virginia Department of Environmental Quality
(VDEQ), and it provides the VDEQ with the authority to require
cleanup. At this time, a required cleanup is not a costly
process, because the VDEQ provides financial
assistance for cleanups. If a release is discovered in
the future, financial assistance may not be available.
Risks to Property and Health
Leaking petroleum may migrate into crawlspaces, basements,
and sumps which can make a house uninhabitable due to the
petroleum vapors. If the release contaminates the groundwater,
it may impact water wells (shallow or deep wells) or surface
water bodies. If a water well is impacted, it is almost impossible
to clean it up. The contaminants are not always detectable
by taste or smell.
Other concerns are surface water bodies such as creeks or
ponds which are usually fed by groundwater. Cleanups of impacted
creeks and ponds can be very costly. If livestock drink from
an impacted pond or creek, their health may be affected.
Selling or Buying Property
Inspections of underground oil tanks are becoming very common
as part of residential real estate transactions for two reasons.
First, if a tank is in-use as part of the heating system for
the house, it is important to know if that system is intact.
Second, if a tank is leaking, the owner of the tank is liable
for cleanup and/or damages caused by it. Currently, financial
assistance from the State through the Virginia Petroleum Storage
Tank Fund (VPSTF) makes cleanups relatively inexpensive, but
buyers are reluctant to purchase a liability which may be
costly in the future.
Also many lending institutions and insurance companies require
that petroleum storage tanks be inspected and properly addressed
(if necessary) before providing a loan or insurance policy.
Third Party Lawsuits
Another reason why oil tanks are often inspected prior to
a purchase is because prospective buyers, insurance companies,
and lenders are concerned about third-party lawsuits. For
example, a homeowner whose basement or water well has been
impacted by heating oil from a neighbor’s oil tank may
sue that neighbor for damages.
Protect Your Real-Estate Investment
For many Americans, buying a home is likely to be the biggest
investment of their lives. Making sure that a petroleum storage
tank is not a major liability is just one part of protecting
that investment.
Science of Leaking Petroleum Storage Tanks and Contaminant
Migration
Over 90 percent of the residential and farm underground storage
tanks that we have inspected were installed prior to 1980,
and over 60% of those tested were found to be leaking. This
percentage is true for in-use tanks as well as abandoned tanks.
The life of an underground tank is normally dependent upon
the conditions of the soil and the tank construction, but
the risk of a leak increases dramatically for tanks older
than 10 years, and tanks older than 30 years are generally
believed to have exceeded their life expectancy.
In our experience, leaking tanks rarely cause any surface
contamination or dead vegetation, and for those tanks that
are in use, one cannot rely on inventory loss to indicate
leakage. As many people are aware, infiltration of water into
a tank is an indication of leakage. But we have also found
that a lack of water infiltration into a tank is not reliable
evidence that a tank is not leaking. Whether or not water
infiltrates a leaking tank is dependent upon the types of
soils, drainage around the tank, and the level of petroleum
in the tank.
How does petroleum move through the subsurface?
Contaminant migration through the subsurface is a complicated
science, and much of it is still not understood. In general,
petroleum leaking from an UST typically flows vertically downward
until it encounters a “boundary” such as the water
table (groundwater). The petroleum is lighter and does not
mix with the water, so it then will float on the groundwater
as it moves through the subsurface. Surface water bodies are
usually fed by groundwater, so creeks, ponds, lakes and rivers
may be impacted by the contaminated groundwater.
The direction of groundwater flow is usually consistent with
the surface gradient, but water wells or sump pumps that are
in use will to a certain extent, “pull” the groundwater
toward them. If contaminated groundwater is within this “capture
zone,” the well or sump will ultimately become contaminated.
How quickly the contaminants move from a leaking tank to
a well, sump or surface water body is dependent upon many
factors such as type of contaminant, soil type, gradient,
and the presence or absence of preferential pathways. It may
take a few days or it may take many years.
Another common way that leaking petroleum may move through
the ground is through man-made preferential pathways such
as utility trenches or construction trenches. Because these
areas have been disturbed, the soils are “looser””
and more permeable, allowing contaminants to migrate easier.
Basements and crawlspaces may be impacted by these pathways
because utility trenches and footings are part of the construction
of the house.
Surface water bodies such as creeks and ponds may be impacted.
These surface water bodies are typically fed by groundwater.
Groundwater contaminated by petroleum will ultimately make
its way to a surface water body. If a pond or creek is used
by livestock for drinking, the contaminants could have detrimental
health effects on the livestock.
These risks are not limited to one’s own property.
Contaminants may migrate to neighboring properties, raising
the possibility of third party lawsuits.
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