Tacoma Water cautiously optimistic that replacing service lines reduces lead

The tap water in the three Lincoln District homes that triggered a regional lead scare last week is testing within safe levels following the replacement of service lines that included short lead pipes, Tacoma Water said Wednesday.

Earlier this month, the utility tested water in service lines leading to the homes in an experiment it said was designed to detect the presence of lead goosenecks, 1- to 2-foot sections of pipe that connect the water main to water service lines outside homes.

What Tacoma Water found was lead levels 25 times the allowable amount for water systems. Two homes had lead levels around 100 parts per billion — and one showed lead at 400 ppb. The Environmental Protection Agency requires action be taken if lead levels exceed 15 ppb.

After the goosenecks were removed and the service lines replaced, the utility took new water samples inside the homes. The results were encouraging, utility officials say.

Water drawn after it had been sitting in the houses’ pipes for at least six hours showed lead levels at less than 1 ppb in all three homes, said Tacoma Water Deputy Superintendent Chris McMeen Wednesday.

“The data looks really good,” McMeen said, but he would not conclusively say replacing the service line solves the problem. He said he is “cautiously optimistic.”

What the utility doesn’t know, since it didn’t conduct tests inside the homes before removing the service lines, is whether the high lead levels detected at the water meters outside were reflected in high lead levels at the homes’ faucets inside.

Answering that question is the focus of testing at 10 more homes where Tacoma Water suspects gooseneck connectors exist.

So far, eight residents have consented to the tests, McMeen said. The utility will test each location four times, on four different days to ensure the water has been sitting in pipes long enough to accumulate lead if it’s present.

The first test will take 12 one-liter water samples with a normal flow of water, as if one were filling a glass of water for drinking.

The second 12-sample set will simulate maximum water flows as if the resident were flushing the system. Tacoma Water has advised residents to flush water from household plumbing for two minutes, and McMeen wants to know if that is enough time to flush lead from a home’s plumbing.

Third, Tacoma Water will draw several samples at the homes’ meters after disconnecting the services lines that could have gooseneck connectors.

Finally, 12 more samples will be drawn from the home after the service line has been replaced.

The results from sampling these 10 homes will inform Tacoma Public Utilities on how to proceed with the 1,700 connections across the city that might have goosenecks, McMeen said.

The utility doesn’t know if goosenecks can be found at all 1,700 locations, only that there is a chance based on the age of the building and utility records that indicate when water service was connected to the building.

“If all samples come back with low lead and no goosenecks, it doesn’t tell us much,” McMeen said.

The utility will pay for lead testing at all of the suspected locations, according to a letter sent to residents and businesses over the weekend. Only 144 of those who received the letter have asked TPU for more information.

McMeen said the utility had sought a cost-effective way to find lead goosenecks. The only way to tell for certain is to excavate the line — an expensive pursuit.

“We’ve looked at scanning technology and talked to researchers and acoustical technicians,” McMeen said Monday. “And we said ‘Why don’t we test the water samples and see if that shows us anything’ — and by golly it did.”

This story was originally published April 27, 2016 at 6:08 PM with the headline "Tacoma Water cautiously optimistic that replacing service lines reduces lead."