Managing Assets, Bursting Pipes at the 73rd Ave / 181st St Project

You may have noticed some traffic delays by the old fire station on 73rd.   Really, it’s not a deliberate attempt to frustrate your commute!

This construction work is actually part of our larger asset management program, a very technical way of saying:

  • The District (which is all of our ratepayers) owns all of NUD’s infrastructure – pipelines, reservoirs, pump stations, etc.  Our staff at NUD take care of the infrastructure, making sure it continues to do its work of bringing you clean drinking water and safely carrying away your wastewater, every single day.
  • Many of the District’s pipelines are older, having been installed over 50 years ago.  Side note: “old” for NUD is nothing in comparison to systems on the East Coast that have been in operation for over 100 years!  Some of the old wood pipelines still exist! 
  • As pipe technology has advanced, NUD has worked to keep pace, replacing our older pipe materials with new.  But with a system containing 270 miles of water main, obviously we have to prioritize which parts to replace.  Here’s where the “asset management program” comes in.
  • Weighing multiple factors, our engineering team determines the risk and consequence of failure for each pipe.  What is the pipe’s age?  What is the water pressure level (higher pressures increasing wear and tear on pipes)?  What is the pipe material (some materials have proven to be less durable and prone to disruptive failure)?  And how high is the potential for damage if the pipe were to fail—is it in a landslide or earthquake zone, or a location that could damage the environment or blow out a road?
  • All of these factors weighed together produce a priority number our engineering team relies on when scheduling projects.

This leads us back to our project situation at 181st and 73rd.  If you live in the Kenmore area, you may remember a pretty dramatic water eruption at this location two years ago.  The break in this 12 inch main spewed 890,000 gallons of water and took crews and contractors many hours to patch up both the pipe and the asphalt overlay.  The replacement project will keep this pipe and the road secure from future disruptive main breaks.

The 2014 main break at the old Northshore Fire Station – this pipe needed an upgrade!

We’re also performing the replacement in the least disruptive and most economical way possible.  The pipe portion on NE 181st St. will be installed by a process called“trenchless pipe bursting.”

How it works:  A machine bores the new pipe into the old one – literally bursting the old pipe into shards as it goes.  Unlike traditional “open-trench” construction, which tears open the entire length of a stretch of road, this method requires smaller, localized excavations in the road, which reduces road restoration costs and traffic impacts.

A crew member guiding the pipe bursting machine into place.

All things considered, we hope our customers in the affected areas count a couple of month’s-worth of traffic delays a reasonable cost for 1,500 LF feet of new, secure water main serving you for many years to come.  If you have any questions about this ongoing project, you may contact our Engineering Director, Dave Kaiser, at 425-398-4422, or

Want to see a pipe bursting in progress?  Check out this video!