Stormwater Management

home-alertCOVID-19: Things are evolving daily and the page below may not be current, get the latest updates on City facilities, services and programs at

Note also that many services are available online to continue to serve the community at this time.

Stormwater runoff is the water from rain or melting snow that is not absorbed into the ground. Stormwater Management controls the quantity and quality of the runoff that is collected from homes and businesses, thereby reducing the risk of property flooding and protecting the health of streams. Runoff is absorb into soil, where it is filtered and replenishes aquifers or it gets safely transported through a system of catch basins, pipes, pump stations, ditches, streams, and discharged to the Burrard Inlet, Coquitlam, Pitt and Fraser Rivers.

The importance of reducing stormwater runoff is essential as excessive runoff is causing erosion and degradation of water quality in stream and rivers. Below are several best practices that homeowners, builders and developers can implement to help protect our natural habitat.

A stormwater management guide, which explains how homeowners can help control excess runoff and protect our natural watersheds, is available here

For homeowners looking to determine and possibly reduce the amount of stormwater runoff from their property, the City has partnered with the Partnership for Water Sustainability in BC to develop a Water Balance express tool. This tool enables homeowners to calculate the current amount of runoff from their property and experiment with actions to try and protect our creeks and watersheds.

Land Use - Rainwater Source Control Measures

All single-family lots

  • 300 mm of topsoil in landscaped areas
  • Hard surfaces graded to landscape areas
  • Encourage the use of permeable paving material and rain barrels

Multi-family, Commercial, Institutional, Industrial

  • 300 mm of topsoil in landscaped areas
  • Hard surfaces graded to landscape areas
  • Encourage the use of permeable paving material and rain barrels
  • On-site infiltration/retention trench or alternative measures
  • Designed to maximize stormwater volume reduction targets in applicable IWMP’s

City Roadways

  • 300 mm of topsoil in landscaped areas
  • Roadside surface swales in unobstructed boulevards, adjacent to parks and open spaces
  • Below grade retention trench in all other locations

Rainwater Source Controls

The City of Coquitlam requires source controls to be implemented at the time of any new development. Required measures are outlined below in the tables.​

Roadside Swale

Roadside swales are shallow grassed or vegetated channels that capture, detain and treat road runoff and convey larger flows. The captured water is infiltrated to the ground to recharge the water table and provide base flows for streams.

Rain Garden

Rain gardens are concave landscaped areas where runoff from roofs or paving is captured, treated and detained before being infiltrated into the soil below. Vegetation helps to filter out contaminants. Rain gardens are designed to have an aesthetic appeal as well as a stormwater function.

Rain Barrel

Rain barrels collect rainwater that lands on your roof so that it can be used to water plants, lawns and gardens. Water that enters the ground rather than a storm pipe helps to maintain base flows in nearby creeks. Using a rain barrel also helps to conserve our drinking water supply by reducing the amount of tap water you use.

On –Site Infiltration Trench

On-site infiltration trenches collect the water from your perimeter drainage system and roof and return it to the ground rather than send it to a storm pipe.  The infiltrated water recharges the water table and provides base flows for streams. A slower return of water to the creeks reduces erosion and damage to aquatic habitat.

Roadside Infiltration Trench

Roadside infiltration trenches collect runoff from the road. The water is collected in an underground trench ground where it can be slowly infiltrated to the soil to recharge the water table and provide base flows for streams.

Pervious paving

Pervious paving is a surface layer that allows rainfall to percolate into an underlying reservoir where it can be stored and slowly infiltrated to the ground. The surface can be porous asphalt or concrete, pavers, or grid structures.

Water Quality Ponds

The purpose of water quality treatment is to clean stormwater flows to an acceptable level for fish prior to discharge into receiving waters. In order to meet water quality criteria, runoff from roadways, lanes, driveways, sidewalks and parking lots should be treated using rainwater management source controls.

Regional water quality ponds are used to make up for short falls in areas where source controls cannot fully meet the water quality treatment targets.

Standard drawings and specifications for the design and construction of source controls is available from the Development Services department.  Additional information for source control design is available in the Metro Vancouver Stormwater Source Control Design Guidelines report (May 2012, KWL).

Engineering & Public Works Customer Service

Engineering Emergency Services for Water, Sewer and Roads

24 Hours a Day, 7 Days a Week

Phone: 604-927-3500