Water Quality Reports

As part of its direction from the County Commission to protect lives and residences, Washoe County has hired an independent third-party lab to routinely test the water in Swan Lake since 2017 when significant precipitation events flooded the lake and caused the water to encroach on homes and properties.

Since 2017, most of the water in Swan Lake is stormwater which means it is primarily run-off from local mountain ranges or rainwater that stays in the lake.

The small amount of treated effluent water that is pumped into Swan Lake has been determined to be “high quality” by the Nevada Division of Environmental Protection.

This high-quality effluent water accounts for a very small volume, between 5% - 6% of the current water in the lake.

On August 8, 2019, the Washoe County Health District (WCHD) was sent and requested to review water sample results from various sampling events of Swan Lake in the late spring/early summer of 2019.

The WCHD is not governed or controlled by the Washoe County Commission, it is a separate entity from Washoe County that derives its authority from state law.

The letter interpreting the independent water quality tests from WCHD can be found linked below.

WCHD determined that there was no concern from the water samples that would lead the Health District to recommend people or pets stay out of the water in Swan Lake.

Additionally, below you will find the most recent water testing results which were commissioned by Washoe County but administered by the independent third-party. These tests are routinely done out of an abundance of caution as part of the protection of residents and maintenance of Swan Lake.

The most basic test for bacterial contamination of a water supply is the test for “total coliform” bacteria.

The most recent tests look for total coliform, E. Coli and other substances as well as overall water quality. 

Total coliform counts give a general indication of the sanitary condition of the water supply.

The results found in this test demonstrate the presence of potential bacteria within the water in Swan Lake for some, primarily total coliform, but not all of the tested parameters.

However, while a presence of bacteria as measured by total coliform occur, the results found in the tests are well below the EPA recommended criteria for both contact and non-contact recreation. Coliform and E. Coli are found in many bodies of water, this is not specific to Swan Lake.

These tests conclude that Swan Lake maintains a “recreational” quality standard, similar to the Lahontan Reservoir and Washoe Lake.

While the water is regularly tested and maintains a recreational standard, the lake is not setup to safety accommodate those would want to boat, paddleboard or swim. Guidance from the Centers for Disease Control dictates that even the highest quality water that is allowed to stand could worsen from a quality standpoint but the County will continue to test the water and post results here.

Washoe County Water Quality Test - 10/31/2019 

Washoe County Water Quality Test - 09/30/2019 

Washoe County Water Quality Test - 08/28/2019

Washoe County Water Quality Test - 7/30/2019 

Washoe County Water Quality Test - 6/25/2019

Washoe County Water Quality Test - 5/23/2019

Washoe County Water Quality Test - 5/06/2019

Washoe County Water Quality Test - 4/17/2019

Nevada State Water Quality Tests - March 2019

Nevada State Water Quality Tests - May 2018

Washoe County Health District Water Test Results - May 2018

Flood Surface Samples - 2017