Subsurface Stormwater Control Measures

As the City of Austin continues to grow and the cost of land gets higher, developers are increasingly placing detention and water quality ponds underground. Detention and water quality ponds are required in most new developments. They are common solutions to help protect the water quality in our creeks and lakes and to help keep the city functioning properly. When they're placed underground, they're called subsurface stormwater control measures. 

Section 1.6.2.E of the Austin, Texas Environmental Criteria Manual defines maintenance and construction requirements associated with subsurface stormwater control measures (link to adopted revisions for your reference). Approved Site Plans for subsurface stormwater control measures can be found by utilizing the Public Search function on the Austin Build + Connect portal.  

Many subsurface stormwater control measures are located under parking structures.

Inspection & Reporting 

While most commercial stormwater control measures are required to be inspected by the City of Austin approximately every three years, subsurface stormwater control measures have additional requirements. The requirements for inspections and subsequent reports are referenced in the Environmental Criteria Manual Section 1.6.2.E.  

• Property owners or managers of subsurface stormwater control measures must submit a 3rd party inspection report sealed by a Texas-licensed Professional Engineer annually.  
• This reporting requirement is for both detention and water quality subsurface stormwater control measures. 
• The annual 3rd party inspection reports sealed by a Texas-licensed Professional Engineer can be emailed to PIDS@austintexas.gov for Watershed Protection review.  

There is no official City of Austin inspection report template requirement. The City of Austin does not endorse, recommend, or guarantee any subcontractor or their work. 

Left: Non-compliant subsurface stormwater control measure (excessive trash). Right: Compliant subsurface subsurface stormwater control (post maintenance).

Violations 

The City of Austin will issue a Notice of Violation for subsurface stormwater control measures that have not received adequate maintenance or have not provided the required annual 3rd party inspection report sealed by a Texas-licensed Professional Engineer. Failure to comply with a Notice of Violation may result in criminal penalties and fines up to $2,000 per day per violation.  

Need for Confined Space Training 

Confined spaces, such as subsurface stormwater control measures and storm drain tunnels, can be dangerous. Only trained and authorized personnel should enter. These underground spaces may lack proper ventilation and lighting and contain hazards such as toxic and flammable gasses, wild animals and sharp objects. When it rains, they can fill with water quickly. People can be swept inside and trapped, resulting in injury or death. 

Open subsurface stormwater control measure access hatch.