Stormwater Dry Well or Infiltrator Registration
What is this service?
Dry wells and other sub-surface stormwater infiltration devices serving uses other than single-family homes are subject to US Environmental Protection Agency (US EPA) regulations. A dry well is considered a Class V injection well, which is defined as a conduit that is deeper than it is wide. Stormwater dry wells may be authorized to operate as long as they are registered with the US EPA, and only inject uncontaminated stormwater. The County of San Luis Obispo currently requires Class V Well registration as part of permitting new development. Read more in the FAQs below.
Who can use this service?
Anyone who has applied for a County construction permit or grading permit can use this service.
Is there a charge for this service?
There is no fee associated with registering Class V wells. The County will verify that the system meets local guidelines as part of review and plan check of new construction and grading permits.
What is the process?
Step 1: Review Guidelines and Finalize Plans
Review the subsurface stormwater injection requirements to verify that the proposed system meets County guidelines. The applicant finalizes their plans based on applicable codes and ordinances and any direction received from staff during the optional pre-application meeting.
Step 2: Submit Plans
The applicant submits a completed application and pays initial application fees for a construction permit or grading permit.
Step 3: Review by Staff
Staff in Planning & Building and Public Works review the application to verify that the plans comply with all applicable codes and ordinances, determine remaining application fees, and ensure that the application is complete.
Public Works will add a Condition to the building permit that requires federal registration of the system prior to final of permits.
Step 5: Satisfy Conditions
The applicant satisfies the building permit condition by provide evidence of system registration to Public Works. A confirmation email and registration number from the US EPA are sufficient evidence of registration.
When and where is this service offered?
This service is available throughout the year during regular business hours except during scheduled holidays.
Location, directions and hours of operation
Click on location name to show hours of operation, directions and phone information
Old County Courthouse Building
Monday - Friday 8:30 AM - 4:30 PM
976 Osos Street Room 200 San Luis Obispo, CA 93408
Tel: (805) 781-5600
Permits/Inspections: (805) 788-2076
Fax: (805) 781-1242
Frequently Asked Questions
Are underground stormwater infiltration chambers covered by this designation?
Yes. Subsurface fluid distribution or infiltration systems (i.e. ADS, Stormtech, or Contech chambers) are included in the Class V well designation.
Do I need to register my septic system?
Only large-capacity septic systems must complete registration as a Class V well. A septic system is considered a large capacity septic system (LCSS) if it receives solely sanitary waste either from multiple dwellings or from a non-residential establishment and the system has the capacity to serve 20 or more persons per day. Please review the US EPA guidance on when a septic system is regulated as a Class V well.
Do infiltration systems serving single-family homes need to register?
No. EPA Region 9, which oversees California, does not require registration of dry wells or other buried infiltrative devices that serve lots with single-family homes.
How do I register a Class V system with the US EPA?
Registration is competed by filling out an online form. The form fields will ask for specific information about ownership and design of the Class V system.
If I need to install a dry-well within an existing stormwater basin, do I need to register the well?
Yes. Any bored or driven shaft whose depth is greater than the largest surface dimension must be registered. The well should be registered, but the basin does not require registration.
What are the County’s guidelines for construction of new Class V systems?
In California, Class V wells are overseen by the US EPA’s Region 9 office. After an inventory form is submitted, the Underground Injection Control (UIC) Program will determine if the well is authorized to “inject”.
The County of San Luis Obispo has adopted subsurface stormwater injection requirements for new Class V Wells or systems. Project plans will be checked against the requirements during drainage and flood hazard review of new construction permits.
The County’s guidelines are outlined on Page 3 of the subsurface stormwater injection requirements. The guidelines are consistent with the policies in place in several California counties.
Why is the County requiring new systems to meet these guidelines?
There are no detailed State or Federal requirements for the design or approval of new Class V systems. However, the County is the local authority responsible for ensuring that new Class V wells do not endanger underground drinking water supplies. The County’s interim guidelines are intended to ensure that new systems meet the minimum requirements set forth by the US EPA to and protect underground drinking water supplies.