What Do You Know about the Landfill?

Landfills contain the leftovers of our daily lives. Often we don’t realize the impact of our thrown-away items because we see only what’s in our home trash can. We’re a consumer society and many things we buy and use end up in the landfill. In King County, we’re doing a pretty good job of reducing and recycling our waste, but there’s always more we can do to keep valuable resources out of the landfill.


Some facts about the Cedar Hills Regional Landfill

  • It opened in 1965. It’s owned by King County and operated by the Solid Waste Division.
  • It’s the only remaining landfill in King County. The others are closed.
  • The landfill is located in Maple Valley, about 20 miles southeast of Seattle, and receives over 800,000 tons of solid waste a year (869,802 in 2015!).
  • The waste received there is from both homes and businesses.
  • The landfill serves the solid waste disposal needs of 1.28 million people, or about 70 percent of King County’s population.
  • Systems at the landfill keep the land, air, and water safe from the effect of landfill gas and leachate (liquid in the landfill that contains pollutants).

The landfill spans 920 acres – that’s nearly the size of 700 football fields! If you’d like to see what this looks like in person, arrange for a tour of the Cedar Hills Regional Landfill for your group or organization. These tours are a unique, fun experience. You may even see eagles!


Watch trailers full of trash tip their loads at the Cedar Hills Landfill in this short, time-lapse video:

Climate change and landfills

We have an effect on our climate with the things buy, use, and put in the trash. The more we buy, use, and throw away, the more greenhouse gas emissions are produced. Greenhouse gases are released when natural resources are removed from the earth, when factories make products, and when trucks, trains, and ships transport goods to consumers.

Methane, a greenhouse gas, results when organic materials (plants, woody materials, food) decompose without oxygen in the landfill. King County’s landfill has a system that collects most of the methane. This gas is turned into energy – both clean natural gas and electricity.

We can all help reduce greenhouse gases when we prevent waste by buying less, buying things with a lower impact on the environment, and recycling and composting.

The current estimate is that the landfill will be full around 2027. However, the Solid Waste Division is exploring ways to extend the life of the landfill until 2040 or later.

How old will you be then?  Where will we put our trash after that? When we throw things away, where is away?