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Water: Class V Wells

Storm Water Drainage Wells

This page will help you determine whether you have a storm water drainage well, learn how to comply with regulations for storm water drainage wells, and find out how to reduce the threat to ground water from your injection well.

Who should read this page?
What is a storm water drainage well?
What is not a storm water drainage well?
Why does EPA regulate storm water drainage wells?
What are the minimum federal requirements for storm water drainage wells?
What are storm water drainage well Best Management Practices?


Who should read this page?

You should read this page if you currently own or operate a device or system that conveys storm water into the ground and you are unsure if it meets the definition of a Class V well, or how to meet the requirements for the well or reduce the well’s threats to ground water.  State, tribal, and local regulators may also find this page helpful.

  • In general, owners/operators of storm water drainage wells include:
  • State and local governments
  • Public and/or private institutions
  • Commercial and/or industrial facilities
  • Community associations
  • Private citizens

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What is a storm water drainage well?

Class V storm water drainage wells manage surface water runoff (rainwater or snow melt) by placing it below the ground surface. They are typically shallow disposal systems designed to infiltrate storm water runoff below the ground surface. Storm water drainage wells may have a variety of designs and may be referred to by other names including dry wells, bored wells, and infiltration galleries. The names may be misleading so it is important to note that a Class V well by definition is any bored, drilled, or driven shaft, or dug hole that is deeper than its widest surface dimension, or an improved sinkhole, or a subsurface fluid distribution system (an infiltration system with piping to enhance infiltration capabilities).

The picture below shows a typical storm water drainage well design.

A typical storm water drainage well design

Answer the following questions to determine if you have a Class V storm water drainage well.

Questions: If Your Answer is Yes... If Your Answer is No...
1. Do you operate a storm water collection system that relies on infiltration to collect and dispose of storm water runoff? Go to question 2. You do not have a Class V storm water drainage well. Stop here.
2. Does your infiltration system discharge to the subsurface? Go to question 3. You do not have a Class V storm water drainage well. Stop here.
3. Does your storm water infiltration system consist of a drilled or driven shaft, or dug hole that is deeper than it is wide? Does it rely on a naturally occurring sinkhole? Does it include any subsurface piping? You have a Class V storm water drainage well and are subject to Class V requirements. You do not have a Class V storm water drainage well. Stop here.

In 1999, EPA completed a study of Class V injection wells to develop background information for use by the Agency to evaluate the risks to underground sources of drinking water (USDWs) posed by Class V wells.  The study describes 23 categories of Class V wells, including storm water drainage wells, and characterizes their use, location, number, potential impacts to USDWs, and regulatory requirements.  Visit the Class V Study page for additional information about storm water drainage wells.

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Definitions

A well or injection well is a bored, drilled, or driven shaft, or a dug hole, whose depth is greater than its largest surface dimension; an improved sinkhole; or a subsurface fluid distribution system used to discharge fluids underground (40 CFR 144.3).

A Class V well is typically a shallow on-site disposal system used to place various non-hazardous fluids below the land surface (40 CFR 144.80).

An improved sinkhole is a naturally occurring karst depression or other natural crevice found in volcanic terrain and other geologic settings which have been modified by man for the purpose of directing and emplacing fluids into the subsurface.

A sub-surface fluid distribution system is an assemblage of perforated pipes, drain tiles, or other similar mechanisms intended to distribute fluids below the surface of the ground.

A dry well means a well, other than an improved sinkhole or subsurface fluid distribution system, completed above the water table so that its bottom and sides are typically dry except when receiving fluids.

What is not a storm water drainage well?

Some types of infiltration systems do not meet the definition of Class V storm water drainage wells. Infiltration trenches are generally larger at their widest surface point than they are deep, and they do not contain any perforated pipes or drain tiles to distribute and/or facilitate subsurface fluid infiltration.  Surface impoundments do not include dug, drilled, or driven shafts.

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Why does EPA regulate storm water drainage wells?

The Safe Drinking Water Act requires that EPA protect USDWs from injection activities, and EPA has set minimum standards to address the threats posed by all injection wells, including storm water drainage wells. 

Storm water injection is a concern because storm water may contain sediment, nutrients, metals, salts, microorganisms, fertilizers, pesticides, petroleum, and other organic compounds that could harm USDWs. 

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What are the minimum federal requirements for storm water drainage wells?

This section outlines the minimum federal requirements for storm water drainage wells. Some states have applied for and been granted authority to implement the Class V UIC Program in their state, including oversight of storm water drainage wells, and may have more stringent requirements. Visit the permitting authority page to find out what agency oversees Class V wells in your state.  It is your responsibility to find out what the specific requirements are in your state.

Class V storm water drainage wells are “authorized by rule,” which means they may be operated without an individual permit so long as the injection does not endanger a USDW, and the owner or operator of the well submits basic inventory information about the well to their permitting authority.

Inventory submission requirements vary by state, but the required inventory information typically includes the facility name and location, name and address of a legal contact, ownership of property, nature and type of injection well(s), and operating status of the well(s).  For more information, visit the page on minimum requirements, or contact your permitting authority.

  • If you have a new storm water drainage well, you must contact your permitting authority before you begin construction.
  • For existing storm water drainage wells, you must stop using the well immediately and contact your permitting authority to find out what you must do. In most cases, you will need to submit an inventory form (PDF) (3 pp, 69K, About PDF) and you may have to wait 90 days to allow the UIC program to authorize your well, after which you may continue using it (unless you are told otherwise).

Authorization to use the well expires once you have properly closed the well.  Proper well closure, also referred to as well abandonment, is a procedure to ensure that the well will not endanger USDWs in the future.  Depending on the well’s design, proper well closure could range from backfilling with clean fill material, to soil excavation, casing removal, and grouting.  Contact your permitting authority for specific instructions on properly closing the well.

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What are storm water drainage well Best Management Practices?

Best Management Practices (BMPs) are physical, structural, and /or managerial practices that prevent or reduce the contamination of USDWs.  The proper design and siting of a storm water drainage well minimizes the likelihood of accidental or routine contamination resulting from either poor operational practices or misuse. 


There are five general categories of BMPs for storm water drainage well BMPs, which can be implemented alone or in combination.  The five general categories relate to:  (1) siting, (2) design, (3) operation and maintenance, (4) education and outreach, and (5) proper closure, plugging and abandonment.  The appropriateness and effectiveness of BMPs vary according to the type, design, setting, and operation of the well. A list of available BMPs for storm water drainage wells (PDF) (4 pp, 22K, About PDF) is available. Consult your permitting authority for additional information and to learn about any location-specific BMPs.

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