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Bacterial Monitoring & Laboratory Results


Maintaining a healthy Lake and beaches

Routine bacterial monitoring is a tool that provides guidance on the general sanitary condition of the Lake at specific locations and times.  Bacterial monitoring does not guarantee prevention of waterborne illness.

Bacteria levels in the Lake are routinely monitored
The City of Lake Elsinore voluntarily contracts with the Riverside County Department of Environmental Health to regularly test the Lake. Tests are performed at eleven sample sites for Total & Fecal coliform bacteria. These two classifications of bacteria are common in the intestinal tract of warm blooded animals and are beneficial to digestion. These and other microorganisms are also found naturally in rivers, lakes and streams.

Related Topics:

Fecal coliform bacteria as indicators of other harmful microorganisms

Total & Fecal coliform bacteria are used as “indicator” organisms for the presence of pathogenic (disease causing) viruses and bacteria. Many disease causing organisms are transmitted by the water route, that is, when water that contains disease causing microorganisms is swallowed. Monitoring Total & Fecal coliform levels is an important tool in assessing the presence of potentially harmful microorganisms, especially after storm runoff, when bacteria levels tend to rise.

E. coli is another type of "indicator" organism that is frequently used to assess the healthfulness of bathing beaches for body-water contact.

Bacteria levels and health standards
Federally funded epidemiological studies (who, what, when, where and how) of waterborne disease have established a statistical relationship between the number of coliforms found in water to negative human health affects. Based on these studies the California Department of Health Services (CA-DHS) established standards for ocean beaches and the State adopted these standards into law. The State has not adopted regulations for fresh water bodies; however, the CA-DHS has developed a DRAFT Guidance document that recommends bacterial standards.  These health standards are shown below.

Sampling the Lake
Sampling of the Lake occurs once a month during the high public use periods from April through September. If an area of the Lake exceeds the health guidelines, the agencies will post warning signs and continue taking water samples every few days until the area passes the CA-DHS recommended standards. If necessary, a sanitary survey of the area is conducted to locate the source of contamination. The same eleven sites are sampled each month. The sampling sites were selected to provide insight into the overall status of indicator bacteria around the Lake. Seven of the sites are sampled from inshore areas, in about 2-feet of water, at the highest use bathing beaches. Three of the sampling sites provide data concerning the main inflow of bacteria from stormwater or inlet channels. One site, the center of the Lake, is generally used as a baseline.

SUMMARY of LABORATORY TEST RESULTS from February 14, 2017:


 Elm Grove Beach

Center of Lake 

 Four Corners Storm Drain

 La Laguna Resort

 Elsinore West Marina

 Weekend Paradise

Playland Park 

 Lakeland Park

Perret Park

 Inlet Channel Area

Outlet Channel Area


(ND = Not Detected);  (N/A = Not Applicable); (Coliform Units = MPN per 100 mls.)


Recommended Bacteriological Standards.

Single Sample Values

Beach posting is recommended when indicator organisms exceed any of the following levels:

  • Total coliforms:   10,000 per 100 ml
  • Fecal coliforms:  400 per 100 ml
  • E. coli:                    235 per 100 ml

Download Map of Sampling Stations.

Download Lab Test Results:







§ 7958. Bacteriological Standards.

(a) The minimum protective bacteriological standards for waters adjacent to public beaches and public water-contact sports areas shall be as follows:

  1. Based on a single sample, the density of bacteria in water from each sampling station at a public beach or public water contact sports area shall not exceed:

(A)     1,000 total coliform bacteria per 100 milliliters, if the ratio of fecal/total coliform bacteria exceeds 0.1; or

(B)     10,000 total coliform bacteria per 100 milliliters; or

(C)     400 fecal coliform bacteria per 100 milliliters.

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