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The Need-to-Know on Sumps and Spill Buckets

So what is a sump? A sump is a subsurface area (pit) designed to provide access to equipment located below ground and, when contained, to prevent liquids from releasing into the environment.

There are various types of sumps, including those beneath dispensers, sumps around the submersible pump (turbine) head, transition/intermediate sumps and spill buckets.


Sumps may or may not be contained. Contained sumps have sides and a bottom, are designed to be liquid tight, and may have a special cover designed to keep water out. Uncontained sumps generally do not have a bottom and are not designed to prevent liquid from entering or exiting the sump. These sumps may use wooden or metal sheeting to restrict the slumping of soil or crushed rock onto the equipment and to prevent the surface pavement from buckling or caving.


Most underground storage tank (UST) systems must have spill buckets at each fill pipe where fuel is delivered into the UST. Some facilities also may have a second spill bucket around the Stage 1 vapor recovery line.

Sumps, including the sumps beneath dispensers, sumps around the STP, transition/intermediate sumps, and spill buckets are common sources of releases. Releases of even small volumes of product can seep into the earth and contaminate soil and groundwater. Inspecting and maintaining your sumps is generally simple and can prevent or minimize the chance of such releases.


Maintaining sumps and spill buckets involves gaining access to them, inspecting them on a regular basis, assessing whether any problems exist and ensuring any problems are addressed. The following is a brief list of questions to ask yourself when carrying out an inspection:

  • Are the lids tight and sealed correctly?

  • Are the sump/spill bucket walls intact?

  • Is the sump/spill bucket free of debris, liquid or ice?

  • Is the sump/spill bucket free of cracks or holes?

  • Are the sump/spill bucket components leak-free?

  • Is the sump free of staining/new staining?

  • Are all penetrations into the sump/spill bucket in good condition?

  • Are the test boots positioned correctly and in good condition?

  • Is the piping and other equipment in good condition?

For serious problems, it's best to contact an experienced UST contractor, like AET Compliance.

AET Compliance (AETC) offers a monthly monitoring program that serves to provide inspection and reporting services to assist owners and operators of UST systems. Their specially trained compliance managers and field inspectors conduct inspections to ensure that facilities maintain equipment upgrades, to confirm that leak detection systems are functioning properly, reconciliation records are up to date and new discharges are handled properly.


AETC has also been assisting their clientele with the issues like STP/Sump corrosion abatement as well as

maintenance and repair of tank risers and dispenser parts. Any inspection results that are cause for concern are brought to the client's attention immediately with appropriate recommendations included.


If you wish to learn more about sumps and spill buckets, we encourage you to read the EPA's manual on inspection and maintenance from which the information in this post was sourced.

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