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Water Information

The City of Lake Oswego supplies water to more than 36,000 customers within Lake Oswego including wholesale water customers like the cities of Tigard and Portland, and the Lake Grove, Glenmorrie, and Skylands Water Districts.

The City wholly owns and operates a municipal water supply system capable of providing up to 16 million gallons per day (MGD) of water that exceeds current federal drinking water standards and our own water quality goals ensuring that your water is safe to drink, available on demand in reasonable quantity and at an affordable price.  In fact, relative to the cost of a single 12-oz container of bottled water or a brand name soft drink, the City can provide you over 1,000 gallons of water for all your in-home and outdoor water needs.

The City's Water Treatment Plant (WTP) produces approximately 2.5 billion gallons of water each year using advanced treatment techniques implemented by a team of seven highly trained staff committed to ensuring your water is safe to drink 365-days a year.

Where does our water come from?
The source of the City's water is the Clackamas River.  This high quality source receives runoff and snowmelt from a 940 square mile area located on the western slopes of Ollalie Butte near Timothy Lake.  Water from the river is withdrawn near the City of Gladstone and pumped across the Willamette River to the treatment plant in West Linn where it is treated to drinking

water quality before being pumped from the plant through a 24-inch diameter pipeline to the City's distribution system, comprised of 15 storage reservoirs, 13 pump stations and about 210 miles of water mains.

What is the City doing to make sure our water is safe and that we will have enough for future needs?
The City operates its water utility using sound financial strategies and performance goals developed in partnership between the Engineering, Maintenance, Planning, and Finance Departments.  The City also is an active partner in several regional and sub-regional organizations whose focus is on planning and coordinating the management and use of Oregon’s water resources.  These groups include the Regional Water Providers Consortium and the Clackamas River Water Providers.  Through participation in these organizations and building relationships with state agencies and other local water providers, the City is embarking on or completing several initiatives including:

  • Implementing a City-wide Water Management and Conservation Plan as approved by the City Council in 2008.
  • Completing a cost-of-service analysis of its water utility and approving a new tiered rate structure for residential customers to encourage wise water use and discourage waste.  The new rate structure will take effect July 1, 2009.
  • Entering into an Intergovernmental Agreement to create a water supply partnership with the City of Tigard.  With a significant amount of its water supply infrastructure in need of replacement, this partnership will reduce the City's capital and operating costs of a new, expanded system by over $60M over the next 25 years.  Tigard will pay more than half the capital cost for the planned expansion and in return is guaranteed up to 14 million gallons per day of water from the jointly owned and operated system.  The City Council approved water rate increases to pay for the City's share of the project scheduled to be completed in 2016.
  • Partnering with Portland State University to develop a predictive water supply model of the Clackamas River.  This model will allow the City and its Clackamas water provider partners to evaluate how existing and future municipal water use from the river will affect flows considering the multiple beneficial uses of the river for endangered salmon, recreation, pollution abatement and drinking water.  The model will also allow scenario development taking into consideration the potential effects of global climate change.
  • Developing a water curtailment plan to guide City actions in response to events that reduce water availability.  This plan approved by the City Council in 2008 recognizes that water shortages caused by environmental events, breakdowns of critical water supply systems or malevolent acts can jeopardize public health and safety.  The plan identifies these events and describes a series of actions the City may take in response depending upon the type of event, severity, and expected duration.

The City over the next few months and longer term plans to undertake several  new drinking water related initiatives including:

  • Developing and implementing a program to offer rebates to residents and businesses who replace inefficient plumbing fixtures with low water use, high efficiency fixtures.
  • Beginning the planning and preliminary engineering necessary to double the size of the City's water treatment and supply system by 2016.  This complex undertaking will involve work in several neighboring cities, the City, and will require construction through and along major natural resources in order to divert water from the Clackamas River and bring it to the west sides of the City.

As these initiatives are completed, the City, through this website, its monthly City-wide newsletter – “Hello LO” and other media sources will endeavor to keep you informed about our continuing efforts and solicit your feedback on how we are doing.