We have two types of sewer systems:

  • Storm sewers and catch basins that collect rainwater and melting snow from roads, sidewalks, roof or gutter downspouts, and building foundation drains which then empty directly to waterways.
  • Sanitary sewers that collect wastewater from homes and businesses (toilets, sinks, laundry, dishwashers, showers) and carry it to wastewater treatment plants 

Coquitlam’s sanitary sewer system plays an important role in good health and hygiene by collecting wastewater from homes and businesses.


Wastewater is any flow from sinks, toilets, or appliances such as washing machines and dishwashers.

Wastewater collected from your home is transported through a network of pipes and pump stations to the regional treatment plant located on Annacis Island. The treatment plant cleans the wastewater before it is released to the Fraser River.

Inflow & Infiltration

Sanitary sewer inflow and infiltration (I&I) is rainwater and groundwater that enters the sanitary system through improper connections and defects. This unwanted water uses up the capacity of the sewer pipe and can cause sewage to back up into your home. It can also cause sanitary sewer overflows to the environment and damage sensitive ecosystems.


There are many sources of I&I including:

  • Lawn and catch basins that are improperly connected to sewer pipes.
  • Leaky manhole covers.
  • Roof and foundation drains that are improperly connected to sewer pipes.
  • Roots growing into sewer pipes.
  • Sewer pipe defects.
  • Uncapped or damaged sewer cleanouts.

Sanitary Connection Grant Program 

The City has a Sanitary Connect Grant program of finding and repairing sources of I&I in the City’s sewer system and you can also help reduce I&I coming from your property. 

You can read more about the City's response to I&I on our Inflow & Infiltration webpage.

Fats, Oils & Grease

Fats, oils and grease (FOG) are by-products of cooking which can solidify in sewer pipes and cause sewage to back up into your house. FOG includes foods such as:

  • Butter and Margarine
  • Cooking Oil
  • Lard
  • Meat Fats
  • Sauces

What You Can Do

It's important to help prevent the clogging of sewer lines by properly disposing of FOG.

  • Scrape your plates clean before washing or placing in the dishwasher. 
  • Wipe grease from frying pans with a paper towel and place it in your green bin.
  • Don’t pour grease down your kitchen sink  - adding soap or hot water doesn’t make a difference. 
  • Store small amounts of fats, cooking oil and grease  in disposable containers and thrown out with garbage, as long as any liquids have been solidified, or take them to the United Boulevard Recycling and Waste Centre,  995 United Boulevard.

Metro Vancouver has more detailed information what to do with fats, oils and grease from your home.

Restaurants and Businesses - Grease Traps

Businesses, such as restaurants, are required to install and properly maintain grease traps on their premises. Grease traps should be adequately sized, regularly maintained and the captured grease should be disposed in accordance to the regional Sewer Use Bylaw.

Do you have a Septic System?

Septic systems require ongoing monitoring and regular maintenance to work properly. If they fail, not only are they expensive to repair and replace but they can pose threats to the environment and human health.

Here are some helpful tips: 

  • Do have your system inspected (every one to three years) and pump your tank (as necessary, generally every 18 – 36 months).
  • Do use water efficiently.
  • Don’t dispose of household hazardous wastes in sinks and toilets.
  • Do plant only grass over and near your septic system. Roots from nearby trees or shrubs might clog and damage the dispersal field.
  • Don’t drive or park vehicles on any part of your septic system. Doing so can compact the soil in your dispersal field or damage the pipes, tank, or other septic system components.