Bacteria levels at Bermuda’s beaches are well within environmental guidelines, according to the latest figures from health watchdogs.

A report by the Department of Health revealed some spikes in enterococci, a group of bacteria used as an indicator of pollution or faecal contaminants, but levels remained well within US limits.

The US guidelines recommend that the 30-day geometric mean does not exceed 35 colony forming units of enterococci per 100 millilitres.

Results between April 30 and August 20 show enterococci levels well below that limit, although levels at two beaches temporarily exceeded 15 CFU per 100ml over the course of the summer.

The first and largest peak was recorded at Snorkel Park on the week of May 21, when testing showed a mean of nearly 20 CFU per 100ml. Levels at the beach fell throughout June, reaching a low of 5 CFU per 100ml before rising again in subsequent weeks.

The second highest spike occurred at the east end of Horseshoe Bay on the week of July 30, with levels again approaching 20 CFU per 100ml before falling.

CFU levels at the centre of the beach and at the west end remained lower, as did the results from Warwick Long Bay.

In the east end, enterococci levels at Tobacco Bay exceeded 10 CFU per 100ml twice, while waters at Shelly Bay reached 5 CFU per 100 millilitres between May 28 and June 11. Levels at Clearwater Beach, John Smith’s Bay and Grotto Bay did not exceed 5 CFU per 100ml.

Centrally located testing sites — including Elbow Beach and Grape Bay — showed consistently low bacteria levels throughout the summer, with no results over 5 CFU per 100ml.

The Department of Health has regularly tested seawater from across the island since 2014, using US Environmental Protection Agency methodology for recreational water quality for marine water, and posted results on their website.

Problems with bacteria in the islands waters arose after a 2013 water quality study revealed levels of enterococci well above US guidelines — although only during rare and sustained weather patterns. The report led to an official warning about Bermuda’s beaches on the US State Department’s website.

Enterococci can enter the sea from a variety of sources, including storm water run-off, animal and seabird waste, failing septic systems, sewage effluent, boating waste and from bathers.