Storm Water Drainage Wells are a subclass of Underground Injection Control (UIC) Class V wells. They are used where there are no storm water sewers, or in conjunction with them, to manage discharges of storm water from surfaces with no or low permeability where natural infiltration of storm water does not occur.
What is Underground Injection?
Underground injection is the subsurface emplacement of fluids by means of a UIC well. Subsurface emplacement of fluids can occur by a wide variety of means but if these ‘means’ meet the definition of a ‘well’ under the UIC administrative rules it is subject to regulation under the UIC Program.
What is a UIC Well?
A UIC well, as defined in R317-7-2, is:
- a bored, drilled, or driven shaft whose depth is greater than its largest surface dimension, OR
- a dug hole whose depth is greater than its largest surface dimension, OR
- an improved sinkhole, OR
- a subsurface fluid distribution system.
Subsurface Fluid Distribution System
A subsurface 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.’ It is important to note that ‘surface’ in the term ‘subsurface fluid distribution system’ refers to the location of the ‘fluid distribution system’ not to the fact that the fluid is being distributed to the subsurface. This is the part of the definition of a UIC well that is most relevant to storm water drainage wells.
What is a Storm Water Drainage Well?
There is a lot of discussion, confusion and downright frustration about what is and what is not a UIC Class V Storm Water Drainage Well.
To provide clarity on this topic EPA prepared a fact sheet in June of 2003 which discussed, generally, what is and what is not a Class V Storm Water Drainage Well. In June of 2008 EPA issued a memo focusing on storm water drainage through Green Infrastructure / Low Impact Development elements. The memo includes a table that addresses individual elements and identifies which of these elements may or may not fall under regulation by the UIC program. In February, DWQ made a presentation to the Utah Storm Water Advisory Council which attempted to add further clarification and to expand upon the two EPA documents.
Do I have a Storm Water Drainage Well?
If after reviewing the EPA documents and viewing the February 2015 USWAC presentation, you are still unsure if your storm water management system is a Class V Storm Water Drainage Well, here are a few questions you can ask yourself.
Does any element of my storm water management system:
- meet the definition of a bored, drilled, driven or dug well or hole whose depth is greater than its largest surface dimension and into which storm water is discharged? If ‘yes’, then it is a UIC Class V Storm Water Drainage Well.
- involve the discharge of storm water into a naturally-occurring opening into the subsurface for which I have constructed a conveyance to direct storm water into the opening? If ‘yes’, then it is a UIC Class V Storm Water Drainage Well.
- exist in the subsurface, for example, under a parking lot, under a landscaped area, under a playing field? If, ‘yes’, then ask yourself ALL of these questions.
- Is the primary function of the subsurface element to infiltrate storm water into the subsurface? If ‘yes’, then it is a UIC Class V Storm Water Drainage Well.
- Is the primary function of the subsurface element to collect and convey storm water AWAY from the location of the subsurface element? This describes the function of ‘underdrains’ in green infrastructure designs. If ‘yes’, then it is NOT a UIC Class V Storm Water Drainage Well.
- Does the subsurface element have dual functionality; that is, to detain/retain storm water for eventual discharge AWAY from the location of the subsurface element AND to infiltrate storm water into the subsurface? This describes chambered systems that have an outlet to a storm water sewer system AND have the capability to infiltrate storm water to the subsurface. If ‘yes’, then it is a UIC Class V Storm Water Drainage Well.
- Does the subsurface element have dual functionality; that is, to detain/retain storm water for eventual discharge of storm water into the subsurface through infiltation? This describes chambered systems that have no outlet for storm water other than infiltration to the subsurface. If ‘yes’, then it is a UIC Class V Storm Water Drainage Well.
Storm Water Drainage Well Requirements
Owner/operators of all UIC Class V wells, including Storm Water Drainage Wells, are required by federal and state UIC regulations to submit inventory information.
The Utah UIC Program has developed Class V Inventory Information Forms to assist owner / operators in meeting this requirement. There is an inventory information form specifically for storm water drainage wells.
UPDES/UIC Storm Water Coordination
The Utah UPDES Storm Water Programs regulate discharges of storm water into waters of the state. In Utah ‘waters of the state’ include ground water therefore we work very closely with the UPDES Section to ensure that all rules and regulations are followed and all requirements for the respective programs are met.
Following are some questions we have been receiving regarding UIC Class V Storm Water Drainage Wells:
Why do I have to submit an UIC inventory information form?
Owner / operators of all UIC Class V injection wells are required by federal and state UIC regulations to submit inventory information prior to injection into the well (R317-7-6.3 and 40 CFR 144.26).
Do I have to submit the inventory review fee for every storm water drainage well?
No. The inventory review fee is a one-time fee required at the time of initial inventory submission for each subclass of Class V injection well at each facility location. After the initial submission of an inventory form for a given Class V subclass, subsequent submittals will be considered as an amendment to the original authorization-by-rule and an additional inventory fee will not be required. See the UIC Inventory Review Fee, and UIC Class V Subclasses for more information.
My storm water management system includes a perforated pipe. Is it a Class V Storm Water Drainage Well?
If the purpose of the perforated pipe is to collect excess storm water that does not infiltrate and to convey it to another location for ultimate discharge then the perforated pipe itself is NOT a UIC Class V injection well. These perforated pipes are referred to as underdrains, interceptor drains, or collector drains. Underdrains are frequently included in the design of infiltration trenches, rain gardens, permeable pavement, and bioswales.
If the purpose of the perforated pipe is to distribute and discharge storm water to the subsurface then it is a UIC Class V injection well.
- Presentation made to USWAC on 11 February 2015—Storm Water Management Systems – When are They UIC Class V? (This PowerPoint is password protected. To view it, download the file, open it in PowerPoint, when asked for a password click on Read Only without entering a password).
- June 2003 EPA Fact Sheet—When Are Storm Water Discharges Regulated as Class V Wells?
- June 2008 EPA Memo—Clarification on Which Stormwater Infiltration Practices/Technologies Have the Potential to be Regulated as Class V Wells by the UIC Program (Annotated)
- EPA Green Infrastructure Collaborative
- EPA Storm Water Drainage Wells
- UIC – SW Expo 2017
- UIC Road School 2016
- UIC Class V Program Coordination