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Lead and Copper Sampling Study - Volunteers Needed August 2013

Water Samples

The City of Lake Oswego is requesting volunteers to assist with a sampling program to collect samples of household drinking water to be analyzed for lead and copper. Sixty household sampling sites will be asked to sample once before the end of 2013 and again in the first six months of 2014.


The Cities of Lake Oswego and Tigard are jointly constructing an expanded water treatment facility to ensure continued high quality drinking water for their communities for many years to come. The expanded plant includes various changes in the treatment processes. One change is the use of sodium hydroxide (also known as caustic soda or NaOH) in place of hydrated lime (also known as calcium hydroxide or Ca(OH)2 ) for pH adjustment and control of corrosion in the water distribution system.

This change triggers re-evaluation of the impact that the treated water has on the levels of lead and copper in the customers’ taps. The US EPA and the Oregon Health Authority have determined that some homes, apartments and businesses were constructed with copper plumbing assembled with solder containing lead before this type of solder was banned in 1988. Brass plumbing fixtures may also contain lead. Under certain conditions, these metals can leach into the drinking water. Lake Oswego residents have been protected from these metals thanks to the addition of lime in the water treatment process since 1998. Periodic samples collected every three years have shown lead and copper levels well below the action levels as defined by federal and state regulations.  The new corrosion control system has been designed and tested in the laboratory to be equally or more effective at corrosion control as the existing system.  However, any time any change in treatment is made to a public water system, it triggers required testing to ensure that the system is working properly.

Household Selection

In order to qualify for sampling, a home must meet certain criteria regarding the material used in construction and the time the construction was completed. The preferred homes, known as Tier 1 sample sites, contain copper pipes with lead solder installed after 1982 and before 1988. City staff is actively seeking homes which meet these requirements. If you believe your home qualifies, and you want to participate, we will work with you to confirm whether your home is a Tier 1 site. City staff will also be reviewing plumbing and building permits for additional locations. We may contact residents directly and request their participation.

Sampling Procedures

Once selected, a clean 1 liter sample bottle will be provided to each homeowner. The sample must be collected by the homeowner from the first draw of water after sitting at least six hours undisturbed. Usually this is from an inside cold water tap such as a kitchen faucet, first thing in the morning, before any other use has occurred in the home (such as showering or flushing). After the sample has been collected, a city representative will pick up the sample and deliver it to the laboratory for analysis. A second round of sampling will be performed at the same locations between January and June 2014.


The results of the analysis will be submitted to the OHA for evaluation.  Individual homeowners will be provided with the results as well. The results will be compared to the action levels of 0.005 mg/l for lead and 0.65 mg/l for copper.

Contact Us

To participate, contact the staff at the Lake Oswego Water Treatment Plant by calling (503)635-0394. You can also contact a member of our sampling program via e-mail at . We will ask for some basic information over the phone and will notify you if your home is a good candidate for this program. Thank You in advance for contributing to the safety of our drinking water!
More Information about  the Lead and Copper Monitoring Program

American Water Works Association (AWWA) FAQS:

Environmental Protection Agency (EPA)  - Lead:

Environmental Protection Agency (EPA) - Contaminants Lead and Copper: