FREQUENTLY ASKED QUESTIONS
Mississippi DEQ New Underground Storage Tank Requirements
October 15, 2008
Question: What must I do if I have water in the containment sump of a piping system
installed after October 1, 2008 or an existing piping system that relies on “Interstitial
Monitoring” as the method of leak detection?
Answer: The water must be removed from the containment sump within 24 hours of
discovery and properly disposed of. If the integrity of the containment sump is in
question, testing must be conducted in order to ensure that the secondary containment
is liquid tight.
Question: Although I have tested the integrity of the secondary containment and it is
tight, I cannot keep water out of the secondary containment. What must I do?
Answer: At no time can water be allowed to accumulate in the secondary containment.
If the system is tested and it is liquid tight, the assumption is that the water must be
entering the containment sumps through the lids. Therefore, you must also make the lids
liquid tight as water cannot be allowed to enter the secondary containment.
Question: I don’t have any problem with water entering my containment sumps – When
must the integrity of the secondary containment be inspected?
Answer: The integrity of all new secondarily contained UST systems (i.e. those installed
on or after October 1, 2008) must be inspected at least once every 12 months unless the
secondary containment is monitored continuously. Continuous monitoring means that
electronic sensors are installed in the secondary containment (including all dispenser
sumps) of the UST system or the secondary containment is monitored by
pressure/vacuum/hydrostatic monitoring methods that alert the owner/operator to any
alarm condition.
Question: Must the integrity of existing secondarily contained UST systems (i.e. those
installed prior to October 1, 2008) be inspected annually?
Answer: Only if the owner/operator is relying on “interstitial monitoring” as the means of
providing the required leak detection and the secondary containment is not monitored
continuously.
Question: A containment sump at a facility installed before October 1, 2008 is not liquid
tight. Does the existing containment sump need to be repaired/replaced so that it is
liquid tight?
Answer: Only if the owner is conducting interstitial monitoring as the method of leak
detection. If the owner is not relying on interstitial monitoring and the containment sumps
are not tight, the piping system is considered to be a single-walled system.
Question: How can the interstitial monitoring requirements be met?
Answer: Monitoring of the secondary containment may be accomplished either visually
or electronically. Visual methods of monitoring would include opening all of the
containment sumps once a month and observing the conditions or manually “sticking”
the interstitial space to determine whether or not fluids are within the secondary
containment. Electronic monitoring would include things like having sensors installed
within the containment sumps or interstitial space that will alert the owner/operator
whenever an alarm condition exists. These electronic sensors may be stand alone
devices or they may be connected to some kind of control box or automatic tank gauging
system. If they are stand alone devices, they must cause a shut-down of the pumps.
Regardless of what method of monitoring is utilized, records must be maintained
demonstrating that the appropriate monitoring occurred for each month the tank system
is in operation.
Question: If I have a failure of one piping system at a facility (e.g. the “regular” grade of
gasoline) that requires me to install a secondarily contained system, must I replace all of
the piping at the facility with secondarily contained piping?
Answer: No, only the piping system that failed and had to be replaced must meet the
secondary containment standards. If however, the owner chooses to replace the rest of
the exiting piping while the job is occurring, then this piping must also meet the
secondary containment requirements.
Question: I am manifolding two existing tanks together. Must the siphon bar between
the two tanks meet the secondary containment requirements?
Answer: The siphon bar must be secondarily contained but, similar to “safe suction”
piping, interstitial monitoring of the siphon piping is not required.
Question: I have had a leak in my existing “regular” gasoline thermoplastic piping
system between two dispensers. Can I simply replace only this one section of “regular”
gasoline pipe between the two dispensers and continue operating as I have in the past
or must the entire “regular” gasoline piping system be upgraded to meet the secondary
containment and interstitial monitoring requirements?
Answer: Yes, you may replace the “regular” piping between the existing dispensers and
continue operating as you always have. Only if you replaced all of the “regular” gasoline
piping from the tank to the most distant dispenser are you required to meet the
secondary containment and interstitial monitoring requirements.
Question: I want to install a new dispenser in an existing pressurized piping system by
extending an existing piping system to the new dispenser. Must the piping that is
installed to connect the new dispenser be secondarily contained?
Answer: Yes, the new piping that is installed must meet the secondary containment
requirements and the new dispenser must have secondary containment. In addition,
because the new piping is part of a pressurized piping system, it must be interstitially
monitored. Practically, this means that a containment sump will also have to be installed
at the existing dispenser where the connection to the existing piping is made.
Question: I want to install a new dispenser in an existing safe suction piping system by
extending an existing piping system to the new dispenser. Must the piping that is
installed to connect the new dispenser be secondarily contained?
Answer: Yes, the new piping that is installed must meet the secondary containment
requirements and the new dispenser must have secondary containment. Because the
new piping is part of a safe suction piping system, it does not need to be interstitially
monitored. However, any dispenser containment sump(s) that must be installed must be
monitored.
Question: I have to replace an existing dispenser that does not have a containment
sump underneath it with a new one because someone accidentally crashed into it. Do I
have to install a containment sump underneath the replacement dispenser?
Answer: No. If the only dispenser you are replacing is the one or ones that were
damaged in the accident, then you do not have to install containment sumps beneath the
replacement dispensers. If you replace other dispensers at the facility that were not
damaged, then all of the replacement dispensers must have containment sumps
installed.
Question: I have replaced all of the dispensers and submersible pumps at an existing
facility and I was required to install containment sumps since I also had to replace some
of the piping components needed to connect the dispensers and STP’s to the existing
single-walled piping. Must I monitor the containment sumps that are now at the
dispensers and STP’s even though the facility has single-walled tanks and piping?
Answer: Yes. Any containment sump that must be installed is required to be monitored.
Monitoring may be accomplished either visually or electronically.
Question: I am replacing the dispensers and changing some of the piping components
at an existing facility that already has containment sumps underneath the dispensers.
Must the existing containment sumps meet the new regulatory requirements?
Answer: Yes. If you are unable to bring the existing containment sumps into compliance
with the secondary containment and interstitial monitoring requirements (i.e. make them
liquid tight) you must replace the containment sumps with new ones that are liquid tight.
Question: I am replacing the motor of an STP but not the entire pump assembly. Do I
have to install a containment sump at the STP?
Answer: No. You may replace any component of the existing submersible pump (e.g.
automatic line leak detector, functional element, packer o-ring, etc…) without triggering
the secondary containment requirement.
Question: I must replace the meter of an existing dispenser. Do I have to install a
containment sump underneath the dispenser?
Answer: No. You may replace any component of the existing dispenser without
triggering the secondary containment requirement.
Question: I am installing a new fueling system that has an underground tank but the
piping is either wholly or partially above ground (e.g. a marina installation). Does the
above ground piping have to be double-walled and do I have to install containment
sumps underneath the dispensers?
Answer: The above ground piping must be double-walled and the dispenser must have
a containment sump. Both the piping secondary containment and the dispenser sump
must also be monitored.
Question: Is a MDEQ certified installer required to perform the testing that is required
on various components of a UST system (i.e. shear valves, spill buckets, overfill
prevention, secondary containment, automatic line leak detectors, etc.)?
Answer: No. The testing can be conducted by anyone as long as no components of the
UST system that routinely contain product are removed during the testing process.
Question: Is a MDEQ certified installed required to conduct any repairs or installation of
new components?
Answer: Yes. If any component of the UST system that routinely contains product must
be altered, repaired or replaced, a person who is certified by the MDEQ as a UST
installer must perform the alteration, repair or replacement.
Question: I am planning to install a new tank, pipe, dispenser or submersible pump after
October 1, 2008. How do I notify MDEQ?
Answer: You must notify MDEQ by submittal of a “Notice of Upcoming UST System
Installation” form. Although MDEQ does not require that you obtain an MDEQ permit for
UST construction activities, you must submit this form at least 30 days prior to beginning
the planned UST system installation.
Question: I am installing/repairing a tank, pipe, dispenser or submersible pump after
October 1, 2008, at an existing facility. The installation/repair is necessary because of an
accident or leak so it is an unexpected installation/repair. The owner wants the work
accomplished as soon as possible – Must I notify MDEQ 30 days prior to beginning any
work?
Answer: No. However, you must still submit the “Notice of Upcoming UST System
Installation” form before performing the installation/repair. Simply request that MDEQ
waive the 30 day notice requirement when you submit the form and describe the
circumstances that caused the unplanned installation/repair.
Question: Will MDEQ provide guidance documents and forms for owners and
contractors to use to conduct these tests and inspections?
Answer: Yes, MDEQ is working on finalizing several of our existing forms and creating a
number of new forms. These will be posted to our website as they become available.