Skip to main content
CommunityWater Quality

Reaching Out: Showing You Where Your Wastewater Flows

By October 28, 2016August 26th, 2020No Comments

King County Wastewater Treatment Division (WTD) works tirelessly to protect public health with award winning wastewater treatment. Because so much of our work occurs underground, we reach out and engage people to help them understand our system, services, programs, and projects. In a new series, we explain how we’re Reaching Out to communities throughout our service area.

There are more than 390 miles of sewer pipelines in WTD’s system. That’s about the distance from Seattle to Coos Bay, Oregon. If you’ve ever taken that drive, you can imagine what it takes to keep those roads in good condition.

Now imagine if that entire stretch of roadway was underground, and it’s not hard to see how much it takes to keep an eye on the sewer system.  While a traffic jam at the surface is an annoying inconvenience, it’s absolutely critical that a “sewer jam” doesn’t occur underground.


In the early days, crews used a technique called “lamping” to make sure pipelines were open.  Crews stationed at one manhole would drop a light down the sewer, and at the next manhole, they would drop a mirror.  A “full moon” reflection meant all was well.

Later, inspection crews would float 35 millimeter cameras down the pipes.  Everything has changed  now that sewer robots are available to cruise the pipelines. The robots are fitted with cameras and track their progress.  A Facilities Inspection crew can view the sewer lines in real time from inside a truck, tracking locations of problem spots that can be located and investigated further.


The truck, cameras, and robots all combine to make great inspection tools. In 2012, WTD’s Community Services staff found that the equipment and the people who operate it make the perfect community outreach tool.


The first step in turning the large, white, and mostly anonymous truck into a rolling wastewater education center was to decorate it with attention-grabbing graphics. The simple, straightforward messages let people know what they should flush (Hint: It’s not doll heads).

Once the graphics were in place, the truck made its debut at the Fremont Fair and Solstice Parade to help raise awareness about the upcoming Fremont Siphon Replacement Project Fremont’s famous summer festival is a performance art event in motion, and turned out to be a perfect fit for the sewer inspection truck.  Costumed and body painted superheroes dodged the sewer robots as their friends drove the bots from inside the truck.  Kids marveled at WTD’s famous “rat in the sewer” pursuit video that ends with a dramatic swan dive by the starring rodent.


And an amazing thing happened. With a usual booth setup featuring display boards, a table, a few educational items and giveaways, most people pass by.  The people who stop spend one or maybe two minutes, pick up a few pieces of paper, and leave.

With the sewer inspection truck as WTD’s booth, about 450 visitors stopped by over two days. They spent 15-30 minutes touring the truck, operating the robots, watching sewer videos, and participating in educational activities. The truck attracted all ages, from kids to adult kids who got a virtual tour of our underground system.


WTD’s Facilities Inspectors are some of WTD’s best ambassadors. They help visitors see what they see, tell them the colorful history of our system, and help them operate the robots that crawl through our system all year long, helping us ensure safe and reliable service.

Of course, the whole setup gets a thorough scrub down before an event, a good thing because kids of all ages are known to get right down and look into the camera face-to-face.


The sewer inspection truck rolls into a few events throughout the year. In 2016, people visited the truck at the Mercer Island Summer Celebration, Cine en el Parque, and Audubon Elementary Back to School Barbecue.


sewerratNo matter what event WTD attends, we try to create a “gee whiz” moment for visitors, and sneak in a little sewer schooling. The next time you’re heading out to fair or festival, be on the lookout for the Wastewater Treatment Division. You never know what kinds of fun stuff we’ll be bringing out to show you.