In response to high lead levels found in pipes outside four customers’ homes in early April, Tacoma Water conducted additional, extensive sampling and testing to ensure it is providing safe drinking water to all customers. It is.
“Our mission, from the first tests we ran, was to make absolutely sure that we are delivering safe water to the people we serve,” said Chris McMeen, Tacoma Water deputy superintendent. “The results give me confidence that our water quality measures – from filtration to corrosion control – are working.”
Results: samples taken inside customer homes
The 464 samples collected inside 12 customers’ homes were well below the EPA action level of 15 parts per billion (ppb) for lead. Ninety two percent were less than 1 ppb, and the highest reading was just above 4 ppb.
At six of the 12 homes, lead goosenecks connected the service line to the water main. Lead levels inside homes with the lead goosenecks were slightly higher than homes without the lead goosenecks, but were still far below the EPA’s action level. The average top lead level of the six homes with goosenecks was 1.98 ppb, while the average top lead level of the six homes without lead goosenecks was .76 ppb.
The results show the utility’s corrosion control efforts are working. Corrosion control ensures that Tacoma’s water does not degrade the piping material it flows through.
Results: samples taken outside customer homes
Samples taken at the meter at homes with a lead gooseneck connected to the water main ranged from non-detectable levels to one sample at 6,180 ppb. Samples taken at the meter without a gooseneck ranged from non-detectable levels to 133 ppb.
The results indicate that when the valve is opened at the meter to shut on or off water and the plumbing – with and without a lead gooseneck – is disrupted, particulates can loosen and be released into the water. That can cause a short-term increase in lead levels. Further testing at the homes showed that flushing the water after opening and closing the valve clears high levels of lead.
“On a day-to-day basis, water quality is very good,” McMeen said. “At those infrequent times when the valve at the meter is turned, lead particulates can be released into the water – with a gooseneck connected to the line and without. Flushing the pipes is quick way to get rid of the lead.”
Responding to the findings
Tacoma Water will continue and enhance its practice of flushing the service line any time water is shut off or on at the meter.
The utility recommends customers:
- Flush their pipes if they turn their water off at the meter by running cold water at an outside or bathtub faucet with the faucet fully open for two minutes.
- Flush their pipes if they haven’t used water for long periods of time (after going on vacation, for example), by running cold water at one tap for 30 seconds to two minutes (or until it is noticeably colder) before drinking or cooking. Taking a shower will flush the pipes.
Tacoma Water will offer water test kits to homes and businesses with a possible lead gooseneck connected to the water main. The kits will be available by July 1. Tacoma Water will contact those customers directly with information about ordering a kit. Customers who are not on the list of having a potential gooseneck connection who want to check their water quality may order sample kits starting October 1.
The utility will continue to remove lead goosenecks as expediently and efficiently as possible, and anticipates replacing all in about five years.