Stormwater Infrastructure Program
The stormwater drainage system consists of 33 miles of open channels and streams, 373 miles of storm sewers, 10,000 storm drains, and approximately 1,000 outfalls, where stormwater leaves the storm sewers and flows into open channels and streams. Through the course of development, more than half of the original stream network in Arlington has been replaced by a system of underground storm sewer pipes. Rain water can flow overland directly to a stream or into the storm sewer system and eventually is discharged to the Potomac River, Pimmit Run, or Four Mile Run.
Most storm sewers in Arlington County are reinforced concrete, corrugated metal or terra cotta. Most of the collection system has been inspected over the past 12 years and is in good condition, with repairs, replacements and rehabilitation implemented as necessary. Reinforced concrete pipes typically have a life span of 75–100 years, and rehabilitation can increase the life span another 25–40 years. Corrugated metal and terra cotta pipes have a significantly shorter life span, and therefore, pipes made of these materials are being proactively replaced with pipes made of reinforced concrete.
Inspecting and maintaining infrastructure is critical to ensuring that it functions well.
Reducing Flood Risk
Reducing risk of flooding for public and private property. Learn more about Reducing your risk of flooding.
Know your flood risk. Is your property in a floodplain? Learn more Flood Insurance Rate Maps and floodplains.