Tribal Shallow Class V Injection Wells in EPA's Pacific Southwest (Region 9)

• About
• Shallow Class V Wells
• Requirements for Class V Wells

About

Under the Safe Drinking Water Act (SDWA), the Underground Injection Control (UIC) Program regulates wells that inject fluids beneath the ground surface. The UIC Program aims to ensure these injection activities do not threaten underground sources of drinking water (USDWs).

EPA has direct regulatory responsibility for the UIC program on all Tribal lands within Region 9, except for the Class II UIC program on the Navajo Nation. Aside from the Navajo Nation Class II UIC program, only shallow Class V injection wells exist on Tribal lands within Region 9.

To learn about UIC deep well injection activities and programs, please visit the EPA national UIC website.

Shallow Class V Wells

Under the UIC Program, subsurface injection practices are classified based on the type of well and fluid injectate. The UIC program regulates the shallow or ‘low tech’ injection of non-hazardous fluids in a category called Class V wells. Class V wells are the most common type found on Tribal lands and include large capacity septic systems, storm water drainage and agricultural drainage wells.

• Large capacity septic systems: These systems qualify as Class V wells if they receive solely sanitary waste either from multiple dwellings or from a non-residential establishment with the capacity to serve 20 or more persons per day
• Storm water drainage wells: These systems inject surface water runoff into the subsurface, they may be called dry wells, bored wells, or infiltration galleries. 
  Agricultural drainage wells: These systems inject excess surface and subsurface water from fields, irrigation tailwaters, animal yard runoff, or feedlot runoff into the ground.

Learn More

• EPA Region 9 Fact Sheet: From Septic Systems to Stormwater Drainage Wells and Beyond (pdf) (832.09 KB, July 2025)
  How EPA's Region 9 is protecting groundwater on Tribal Lands by managing Class V Underground Injection Control (UIC) wells

Requirements for Class V wells

All owners/operators of Class V wells must:

1. Register the injection well(s) with EPA’s UIC program (see 40 CFR 144.26).
2. Operate and maintain injection wells in ways that do not risk polluting underground sources of drinking water (see 40 CFR 144.12).

Most Class V wells are “authorized by rule” by EPA, meaning no special permit is needed if the above requirements are followed. However, local, state, or Tribal rules might be stricter than federal ones, and it is the responsibility of the owner or operator to ensure compliance with all regulations.

Note: There is no cost to register your Class V injection well with EPA. If you have any questions or need help, please contact the Tribal UIC Wastewater Contact above.

Upon submission of the well registration, EPA will evaluate the submittal to determine if the injection activity can be authorized by rule. EPA may require the registrant to report certain design and operational data to assist in this determination. Generally, a federal UIC permit will not be required for these systems. Authorization by rule does not imply endorsement of any engineering plans provided with the registration information. Construction of the wastewater treatment system should not commence prior to well registration.