Underground Stormwater Detention Facilities

In cities where vegetated surfaces have been replaced with buildings, streets, and parking lots, stormwater runoff occurs can cause erosion, damage waterways, and destroy aquatic habitats. Underground detention vaults are often installed in urban settings to manage stormwater runoff.

iSTORMWATER provides underground stormwater detention facility maintenance in Washington, DC; Maryland; and Northern Virginia. We help commercial property owners sustain a functional, compliant system.

Call us at (443) 699-2828 or contact us online to learn more about how we can help.

What is an Underground Stormwater Detention Facility?

Stormwater management facilities come in many varieties. This particular option is a belowground stormwater structure designed to manage runoff from developed sites in urban settings. Underground detention facilities are often buried beneath parking lots and other solid surfaces, making them ideal if there is insufficient space to build aboveground detention facilities.

The primary purpose of underground stormwater structures is to manage runoff quantity. They delay the delivery of water downstream, which helps prevent flooding and erosion. Some are also attached to media filter banks to remove chemicals, oil, sediment, and other pollutants that would otherwise flow into rivers and streams.

iSTORMWATER can maintain your underground stormwater detention facility. Give us a call at (443) 699-2828 to schedule services in Southern Maryland, Northern Virginia and Washington, DC.

Maintenance for Underground Stormwater Detention Facilities

Belowground stormwater systems are often constructed from high-density polyethylene filtration chambers, but many material variations are in use today. In fact, there are so many sizes, locations, and material options that no one-size-fits-all maintenance protocol exists. While large vault-type systems may require maintenance annually, smaller catch basin inserts or filter units with less capacity might need more frequent cleaning to maintain peak performance.

Many stormwater facility manufacturers provide a recommended inspection and maintenance schedule that must be carried out for compliance purposes. Property owners should expect to give extra attention to their underground stormwater detention systems during the first year of operation. Monthly or quarterly inspections are needed at this time to ensure the newly installed structure is performing as intended. After that, the inspection schedule may be modified to meet specific stormwater permit requirements.

Inspection & Maintenance of Underground Stormwater Detention Facilities

With underground detention systems, the low-flow orifice is the key point in the system’s maintenance. This device regulates stormwater outflow, so it must remain unobstructed to function as intended. Therefore, the minimum maintenance required for underground stormwater facilities includes routinely removing trash, sediment, oil, hydrocarbons, and other debris.

During an inspection from iSTORMWATER, we measure sediment accumulation with a stadia rod, measure oil and hydrocarbons with a Teflon bailer, and dip out floating solids as needed. When cleaning is required, we use a sump-vacuum truck to remove captured sediment and floatables. We also replace filters and absorbent media once they reach capacity. We’ll provide you with a maintenance and activity report, complete with photo documentation and a list of the services we performed for your records.

If it’s time for your next detention facility inspection or maintenance visit, please contact us at (443) 699-2828.


Enjoy comprehensive stormwater management services from iSTORMWATER, an industry leader with over 20 years of experience serving property owners in the the DC metro area. Our highly trained and skilled technicians are committed to your satisfaction. In fact, we guarantee the highest level of quality and attention to detail to help you avoid violations and penalties while preserving business capital.

For proven underground stormwater services in Southern Maryland, Northern Virginia and Washington, DC, please call iSTORMWATER at (443) 699-2828 or contact us online.


Real Results

iStormwater LLC was an excellent choice. They made the process of the Storm water pond repairs seamless. They took charge of the project and got the project approved and passing the inspection. We highly recommend them and would use them again.

Lyonswood HOA

Incredible stormwater management service. The owner John consulted on a property I manage and ended up saving us thousands of dollars in environmental fees from the government. Now, our property is compliant with the EPA and we have a great partner to keep us maintained on storm water regulations over time.

Kelly E.
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