A
storm drain,
storm sewer (
US),
surface water drain/sewer (
UK),
stormwater drain (
Australia and
New Zealand), or simply a
drain or
drain system is designed to
drain excess
rain and
ground water from
impervious surfaces such as paved streets, car parks,
parking lots, footpaths,
sidewalks, and
roofs. Storm drains vary in design from small residential
dry wells to large municipal systems. They are fed by
street gutters on most
motorways, freeways and other busy
roads, as well as towns in areas which experience heavy rainfall,
flooding and
coastal towns which experience regular
storms. Many storm drainage systems are designed to drain the storm water, untreated, into rivers or streams.