By Doug Curlee | Editor at Large

You may not even know it’s happening

Seldom does a week go by without news of yet another water or sewer pipe failure somewhere in San Diego.

There’s a $4.2 million project going on in the Del Cerro-Allied Gardens area right now, working to see that doesn’t happen. It’s one of many such jobs being done, or in the planning stage citywide.

“There are a lot of areas around San Diego where this needs to be done. It’s well-known that there are many miles of very old pipe under our streets,” said resident engineer Neda Shahrara while watching over a work crew fixing pipes on the corner of Lance Way and Bounty Street in Allied Gardens. “Too many pipes are failing.”

For the most part, it turns out that the failed pipe is an old — often very old — corrugated steel pipe that’s been in the ground for 50 years or more. They are old. They corrode. They simply come apart, necessitating an expensive, time-consuming, street-damaging excavation to replace the pipe with PVC plastic pipe that has a longer life.

It takes a lot of time and work to get all that done.

But it doesn’t always need to be that way. Often, those old pipes can be rehabilitated by a relining process. It’s done with new, non-metal pipe inserted into the old pipe. A resin is injected around the new pipe, binding it to the old pipe. The resin is hardened by hot water or steam.

When it cools, you see that it’s firmly attached to the inside of the old pipe, completely sealing any possible leaks or breaks in the pipe before it has a chance to cause major trouble.

It’s also a lot cheaper than digging up the street and replacing the old pipe, and lot less damaging to the streets.

The fix is done without the need for a full work crew, backhoes, shovels, jackhammers and whatever else would be needed to create a great big hole in a street that may never be as good of a street as it was before the pipe replacement. Two men were doing the job at the Allied Gardens site, with the aid of their underground television camera to show them what’s needed.

If this sounds familiar to you, it should.

It’s exactly the sort of fix being implemented in Flint, Michigan, where lead from old pipes disastrously poisoned the city water supply, leading to lead poisoning of people who had to drink that water. There are other cities around America looking at the same kind of problem, and at least thinking about the same sort of solution.

There is no indication we’re facing any sort of Flint problem in terms of water quality. Ours is the simple problem of age-old infrastructure that’s way past its expiration date.

The relining process can be used for any size pipe that needs it. It’s valid for pretty much any size pipe that needs care.

“It’s workable for pipes from the size of these all the way up to huge 100-inch pipes used to transfer water from reservoirs to other reservoirs, or on jobs like the state water project,” Shahrara said.

The philosophy is simple.

Find the little problems and fix them before they become great big problems.

There’s another water problem we’ve been keeping an eye on as well. That would be the January sinkhole on the edge of Interstate 8 near College Avenue. It’s not the first Caltrans sinkhole we’ve seen, and it probably won’t be the last. To a degree, Caltrans has the same problem with older metal pipe that San Diego has, but not as advanced yet.

The January sinkhole was fixed quickly, and Caltrans spokesman Ed Cartagena points out there isn’t generally as much demand on the Caltrans freeway drainage system as there is on San Diego’s pipelines.

“Our pipes don’t get water flow unless it’s raining, where the city’s pipes are in use constantly. We are always checking our systems to make sure they’ll work when they need to. So far, we’re not thinking about relining our pipes.”

Caltrans has plenty of systems to keep an eye on. In District 11, which is basically the San Diego area, there are 18,000 smaller pipes that feed into the bigger main disposal pipes — all 10,000 of them.

That keeps Caltrans’ pipe crews busy enough.

—Doug Curlee is Editor at Large. Reach him at [email protected].