Project Background & Summary

Newcastle maintains over 35 miles of stormwater pipes, mostly located under our streets. Many of these pipes are reaching the end of their life. Some are 70 years old! When pipes under the street fail, they can cause sinkholes, damage roadways, inconvenience residents, and harm our environment. In May of 2017, a stormwater pipe on SE 73rd Place failed and caused a sinkhole.

Sinkhole on SE 73rd Place

The sinkhole and emergency repair of the pipe and roadway forced Newcastle to close the road. The repair cost $46,000 plus many hours of staff time and it inconvenienced residents and roadway users. To prevent pipe failure in the future, Newcastle created the Storm Pipe Rehabilitation Program (S-038). The program proactively evaluates existing pipes, prolongs the life of aging pipes and repairs damaged pipes to prevent catastrophic failures. The S-038 program reduces hazards, prevents flooding and pollution, and saves rate payers money by preventing costly emergency repairs.

What Are We Doing?

Most of the City's stormwater pipes are buried under our roads. Instead of assuming they need to be replaced based on their age, we use a robotic camera to view and evaluate the pipes. Pipes are selected for evaluation based on their age and the material they are made from. The robotic camera creates videos of the pipes. The videos are viewed by City staff or consultants and pipes are assigned a score based on their structural condition. 

Example of Failing Pipe
Example of Failing Pipe

The pipes with the worst scores are severely damaged and need to be repaired or replaced. Repairs and replacements are prioritized based on the pipes locations and usage. Pipes under major roadways are the highest priority.

Learn more about pipe scoring here.

Repair Types

After we determine which pipes need to be repaired or replaced, we must determine the best repair or replacement technique. The following techniques are commonly used in Newcastle.

Trenchless Repair: Uses a robot or equipment to re-line the pipe. Re-lining equipment is inserted into the pipe. It pulls a liner through the pipe. The liner cures inside the pipe creating a new rigid surface inside the pipe. This type of repair is less expensive and does not require digging up the roadway. It can be used to repair small cracks and fractures in a pipe.

Trenchless Spot Repair: Uses the same technology as trenchless repair to repair a small section of pipe.

Open Cut Full Repair: Cut open the road, dig up and replace whole pipe. This is the most expensive and invasive form of pipe repair. 

Open Cut Spot Repair: Uses the same technology as open cut full repair but replaces a small section of pipe.

Learn more about pipe repair technology here. 

What Has Been Completed?

2018:  Began evaluating pipes in Donegal, Newport Woods and Evergreen Terrace neighborhoods. 

Map of work areas
Map of pipes being evaluated

2019: Completed the first planned repair project in the S-038 program by repairing a pipe in the Mile Post neighborhood. Learn more about the project here.

2020: Developed pipe scoring matrix and prioritized repair work. 

Project Location, Plan, & Timeline

Newcastle's goal is to continue evaluating about 2.5 miles of pipe per year. We will prioritize pipe repairs as we find damaged pipes. We will add information about pipe repair projects as it becomes available.

Partners & Funding Support

In 2018 Newcastle received a $67,000 Flood Reduction Grant from the King County Flood Control District. This grant paid for most of the cost of the 2019 Mile Post pipe repair project.

In 2020, Newcastle received a $53,000 WaterWorks Grant. This grant is paying for repair and replacement of degrading and failing stormwater pipes.

Mayor Newing accepts check from Council Member Dunn
Newcastle Mayor Newing accepts check from King County Councilmember Reagan Dunn
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