With the onset of the rainy season, SDCI is reminding builders working in Seattle to inspect and maintain any temporary storm drain inserts they have installed as part of construction projects. The inserts, also known as storm drain socks, are used on many construction projects to catch sediment not captured by other required construction-related erosion control measures.
All construction sites must have on-site erosion control measures to prevent soil from washing away. The use of storm drain inserts is an added level of protection for water quality.
Stormwater Code standards for the use of the socks include the following:
- Inspections by the builder should be made on a regular basis, especially after large storms. Inlet protection devices shall be cleaned or removed and replaced when sediment has filled one-third of the available storage. Product manufacturer standards should be followed.
- Do not wash sediment into storm drains while cleaning. Spread all excavated material evenly over the surrounding land area or stockpile and stabilize as appropriate.
- Only place the storm drain inserts in the area directly adjacent to the project site.
- In the event of heavy rain, remove the socks to prevent local flooding.
For reference, see SDCI Director’s Rule 17-2017, SPU DWW-200, Stormwater Manual, Volume 2, Chapter 4, Section 4.3.3.
Any questions on active construction site drainage or erosion control measures may be referred to the SDCI Site Inspection Team at (206) 684-8600.
To help prevent flooding, the public is urged to clear clogged drains where it is safe and practical to do so. Flooding should be reported to Seattle Public Utilities at (206) 386-1800.