Beach Advisories

The Health Department collects water samples from various beaches throughout the County from Memorial Day through September. Samples are analyzed for various water quality parameters, including bacteria levels, to protect public health and to prevent the spread of disease. No swimming advisories are issued if bacteria levels exceed water quality standards.

Sampling Date Lake Michigan Locations Single-Day Geometric Mean 30-Day Geometric Mean Results
1 09/02/2008 Grand Haven City Beach 0.0 N/A
2 09/02/2008 Grand Haven State Park 0.0 N/A
3 09/02/2008 Rosy Mound Recreation Area 0.0 N/A
4 09/02/2008 Windsnest Park 0.0 N/A
5 09/02/2008 Kirk Park 0.0 N/A
6 09/02/2008 Holland State Park, Lake Michigan 0.0 N/A
7 09/02/2008 North Beach Park 0.0 N/A
8 09/02/2008 Kouw Park 0.0 N/A
9 09/02/2008 Tunnel Park 0.0 N/A

Sampling Date Inland Lake Locations Single-Day Geometric Mean 30-Day Geometric Mean Results
10 09/02/2008 Grose Park 0.0 N/A
11 09/02/2008 Dunton Park 0.0 N/A
12 09/02/2008 Lakeside Park 0.0 N/A
13 09/02/2008 Holland State Park, Lake Macatawa 0.0 N/A
14 09/02/2008 Georgetown Community Park 0.0 N/A
15 09/02/2008 Fallen Leaf Park 0.0 N/A
16 09/02/2008 Maplewood Lake Park 0.0 N/A
17 09/02/2008 Pottawattomie Park 0.0 N/A

Sampling Procedures

The health department collects water samples at beaches to determine if the water complies with standards set by the Michigan Public Health Code. Samples are generally taken one foot below the surface in water that is between three and six feet in depth. A laboratory using Environmental Protection Agency approved testing methods performs the analysis. Results of the analysis are available after approximately 28 hours, so water-testing results are reported the following afternoon. E. coli bacteria are counted and judged against standards established by state rules of 300 E. coli per 100 milliliters of water. The health department takes a minimum of three samples each time a beach area is monitored. The daily geometric mean calculated from these samples must be below 300 for the water to be considered safe for swimming. Sometimes one or two of the samples may be above 300, but if the daily geometric mean is below 300, the beach is not in violation of the water quality standards.

A minimum of five sampling events (consisting of at least three samples per event) must be collected within a 30-day period for the results to be considered a reliable indication of water quality. After 30 days, a geometric mean is calculated for all the individual samples collected within that time frame. This 30-day geometric mean must be below 130 E. coli per 100 ml for the water to be considered safe for swimming.

A "No Swimming Advisory" is issued if either the single-day or 30-day geometric mean bacteria count exceeds the state established limit. If a beach is closed due to bacterial contamination, the health department will continue to monitor the water quality at the beach and will permit the beach to reopen for swimming when bacteria levels fall back within acceptable levels. It is possible that a beach could be closed for swimming but other recreational activities at the beach may still be available.

Trends in Water Quality Sampling

Sampling conducted by the Health Department since 2002 demonstrates that the water quality at our Lake Michigan beaches is usually very good. Nearly 98% of all samples collected have been acceptable for swimming. However, the water quality does occasionally present a health risk. The Ottawa County Health Department is working to identify the causes of poor water quality in order to better manage these rare situations. For the past couple of years, the Health Department has been conducting sanitary surveys of our Lake Michigan beaches. These surveys help us collect data regarding environmental and meteorological factors present during the time of sampling. These data can then be used to correlate those factors - such as rainfall, water temperature, current direction, sewage spills, and others - with impaired water quality. As a result, it is hoped that the Health Department will eventually be able to construct a water quality forecasting tool which will be able to provide the public with more timely advisories.

While this sanitary survey project is still in its data collection phase, some interesting trends have been noticed at our Lake Michigan beaches:

  • 82% of all E. coli exceedances occur in the later part of the swim season (between July 15th and Labor Day).
  • There have only been a total of three advisories prior to July 4th of any year since 2002.
  • Only 19% of E. coli exceedances persist for more than one day.
  • Cloudy and overcast conditions correlate to impaired water quality more strongly than any other factor identified to date.
  • Heavy precipitation also seems to correlate positively with higher levels of E. coli bacteria.
  • Strong South to North lake currents (>20 meters/minute) correlate with higher levels of E. coli bacteria at the beaches immediately South of the pier in Grand Haven.
  • Large algae blooms late in the swim season seem to harbor large populations of E. coli bacteria.

The Ottawa County Health Department will continue gathering data with the sanitary survey tool and will provide further findings when appropriate.

Preventing Water Illnesses

It is important to remember that while our Lake Michigan water is usually of the highest quality possible for natural surface water, it is never drinking water quality. Recreational water illnesses such as Cryptosporidium, Giardia, Camplyobacter, Shigella, Salmonella, Hepatitis, and others do make people sick every year. Please follow these recommendations when enjoying our beautiful beaches:

  1. Do not swallow the water. Ingestion is the primary route of infection for waterborne illnesses.
  2. Wash your hands before eating. Surface water and sand harbors bacteria, viruses, and parasites.
  3. Use the restroom prior to swimming and direct children not to relieve themselves in the beach water. Human waste carries infectious micro-organisms and contaminates our beaches.
  4. Do not swim if you have been ill, and do not let sick children swim either.
  5. Avoid swimming immediately after heavy rainfalls or during periods of extended cloudiness. Experience has shown that these weather conditions tend to coincide with higher E. coli bacteria levels.
  6. Avoid swimming in murky water or in water which looks polluted.
  7. Do not feed the seagulls and do not leave any trash on the beach. Studies have shown that seagulls contribute significant amounts of E. coli to the beach environment.

For questions about beach water sampling please call 616-393-5645.

Safe Swimming
Although the health department does not deem a beaches unsafe based on weather conditions or wave action, we encourage our residents and tourists to swim safely. The miles of beautiful shoreline are inviting, however we all should be reminded to respect the water. Rip currents and undertows can be very strong and very dangerous. Please visit http://www.ripcurrents.noaa.gov/ for more information.

Beach Advisories and Closings throughout the State of Michigan

Healthy Swimming (CDC)