Frequently Asked Questions

Below is a list of Frequently Asked Questions related to drinking water, water treatment, water distribution, and water quality.

Where does my water come from?

The highly protected and pristine Clackamas River is the drinking water source for the City of Lake Oswego. This high-quality water source receives runoff and snowmelt from a 940 square mile area located on the western slopes of Ollalie Butte, near Timothy Lake, in the Mount Hood National Forest. Learn more here

How is my water treated?

The water treatment plant utilizes a state-of-the-art water treatment process, known as conventional filtration plus ozone. Learn more here. 

What should I do if my water is discolored?

Sediment often settles in our water pipes and from time to time that may be disturbed which can color the water coming out of our taps. We recommend running your bath tub at full speed with cold water at for about ten minutes or until the water runs clear, to help flush the water in your lines. If the discoloration continues, please call Public Works on 503-635-0280.

Why does the taste and smell of my water sometimes differ?

Water naturally varies in taste and odor at different times of the year. Taste and odor problems can come from new or old pipelines, plumbing fixtures, or changes in water quality. Customers may notice changes predominately during weather/seasonal changes. These changes are closely monitored to ensure that they do not affect the safety of the water.

We recommend running your bath tub at full speed with cold water at for about ten minutes or until the odor improves, to help flush the water in your lines. If the odor continues, please call Public Works on 503-635-0280.

Why does my water have a chlorine taste and odor? How do I improve the taste?

Public water systems are required by state and federal safe drinking water laws to maintain a residual chlorine level in the water to keep it safe from microbial contamination. Low levels of chlorine, below 4 ppm, are considered safe for drinking water by the EPA.

If you do not like the taste of chlorine in the water, you can remove it by placing an open pitcher of water in the refrigerator to let the chlorine dissipate for at least 48 hours or run the water through a granular activated carbon filter that is rated to remove chlorine.

Does the City have a brewer’s report?

Yes! Please call the Water Treatment Plant to obtain a copy 503-635-0394.

Is my water hard or soft?

The water from the Clackamas River is considered soft. It is around 25 ppm or 1.5 grains per gallon of hardness.

Is fluoride added to our drinking water?

No. The Lake Oswego Tigard Water Treatment Plant does not add fluoride to the water and there is no detectable natural fluoride in the Clackamas River source. Fluoride is a naturally occurring trace element in surface and groundwater. You may want to consult with your dentist about fluoride treatment to help prevent tooth decay, especially for young children.

Who do I contact if...

...I need to set up or disconnect my water service?

Complete this form or view this page for more information.

...I need to pay my water bill? 

Visit Utility Billing. 

...I need to shut off my water?

If you have an emergency or would like to schedule an appointment to have your water turned off for needed leak repairs, please call Public Works at (503) 635-0280. If you have an emergency after business hours and need to get your water turned off, please call the non-emergency dispatch at (503) 635-0238.

If you have any other reason for needing your water turned off, please call Utility Billing at (503) 635-0265. Appointments can be made Monday through Friday from 8 am - 2:30 pm. There is no charge for this service during regular business hours, however, if you require after hours assistance there is a charge of $80.00.

...I would like to find out what my water pressure is? 

The City prefers to make a physical reading onsite to ensure the most exact pressure reading possible. If you would like to meet a Water Utility worker at your residence, appointments can be made Monday - Friday from 8 am to 2:30 pm. Contact Public Works at (503) 635-0280 to request a water pressure test.  

...I notice my water meter is leaking?

Please call Public Works at (503) 635-0280. 

Should my water be treated before use with pet fish?

Yes. Your drinking water contains disinfectants to prevent bacterial growth. These disinfectants can kill fish. Chlorine may be defused by adding appropriate chemicals that are available at most pet stores. Chlorine may also be removed with a granular activated carbon (GAC) water filter or by letting a container of the water sit exposed to the atmosphere (uncovered) for at least 48 hours.

Some fish, particularly tropical fish and koi, are also sensitive to rapid changes in the temperature and pH of the water, even small changes. If you are going to change the water in an aquarium or pond, or add a significant amount of new water, consult an experienced fish care expert for tips on how to accomplish this without shocking or killing the fish.

Does the City offer free lead testing kits?

Yes, the City offers free lead testing to its water customers. The main source of lead in drinking water is typically from household plumbing or components associated with service lines.

If you are concerned about the levels of lead in your home, you can pick up a test kit and instructions at the main reception desk at City Hall, 2nd floor. This testing kit is for water only, not paint or other surfaces (test kits for lead paint are available at most hardware stores). For questions about lead testing or your drinking water, call the Water Treatment Plant at 503-635-0394.

Are there Cyanotoxins (algae blooms) in my drinking water?

No, there have never been any cyanotoxins detected in Lake Oswego’s drinking water. The Lake Oswego Tigard Water Partnership and the Clackamas River Water Providers have monitored the Clackamas River Watershed for many years for cyanotoxins. Although we have detected low levels of these compounds in the North Fork Reservoir and on the Clackamas, no toxin has been detected in Lake Oswego’s finished drinking water. 

Can the water treatment plant remove Cyanotoxins?

Yes! The water treatment plant’s robust state-of-the-art treatment provides multiple barriers to remove algal toxins, including ballasted flocculation, ozone treatment, biological treatment, and final disinfection with chlorine to effectively treat these compounds. 

Is my water tested for PFAS?

Yes, the fifth Unregulated Contaminant Monitoring Rule (UCMR 5) requires sample collection for 30 chemical contaminants, including 29 PFAS (per- and polyfluoroalkyl substances) and lithium in Lake Oswego’s drinking water. There have been no detectable amounts of these chemical contaminants listed in UCMR 5 in Lake Oswego’s drinking water. For more information about PFAS, click here. 

What about Cryptosporidium?

Cryptosporidium is a microorganism (protozoan) naturally present in surface water supplies throughout the world. Surface water supplies are particularly vulnerable if they receive runoff or pollution from human or animal wastes. Since wildlife inhabit the Clackamas River Watersheds, managing agencies regularly monitor for Cryptosporidium. Occasionally, this monitoring detects low levels of Cryptosporidium, however, Cryptosporidium has never been detected in Lake Oswego’s drinking water.

How do I find out who my water provider is?

Type your address in the form here. 

Does the City have a water interactive map I can view? 

Yes, here is a link on LO Maps. 

Where can I learn more? 

Contact Information

Water Treatment Plant: (503) 635-0394

Public Works Maintenance Operations: (503) 635-0280