In this summer of record heat and rain, such as the 4.2 inches that soaked Oahu on June 25 followed the next day by sewage spills and an islandwide brown-water advisory from the state Department of Health, beachgoers might want to do a water-quality check before diving in.

One easy warning sign is brown water. After rainstorms, Crystal Thornburg-­Homcy, 37, a North Shore professional surfer with a 5-year-old daughter, said she stays out of brown water as a rule.

“We love swimming at Waimea Bay in the summertime. It’s very family-oriented,” she said. “But I’m very aware of when the river opens (to the sea) after rains, when everything comes down.”

But clear blue water can also harbor pollutants, which is why the Health Department’s Clean Water Branch and the nonprofit Surfrider Foundation’s Blue Water Task Force test for enterococcus, a bacterium that indicates the presence of fecal pathogens, microorganisms that can cause gastroenteritis and ear, eye, nose and throat infections.

The threshold bacteria level for a higher risk of illness, set by the U.S. Environmental Protection Agency, is 130 enterococci per 100 milliliters.

This was far exceeded at several Honolulu beaches Sunday, when the Surfrider Foundation found levels of 1,081/100 mL at Ala Moana Park, 1,670/100 mL at Black Point, 689/100 mL at Kahala Seawall and 2,382/100 mL at Kuliouou Stream.

In interviews with the foundation and the state about the causes of high bacteria levels, the Honolulu Star-Advertiser learned that the two organizations, while united in their missions to inform the public and reduce the risks of exposure to waterborne illnesses, had somewhat differing approaches regarding where to test and when, and how much information is provided.

Both organizations do their best with limited resources. The Clean Water Branch has three staffers who test Oahu’s 130-odd beaches, and one each for Maui, Kauai and the Big Island; Surfrider’s testers are all volunteers.

At popular beaches such as Waimea, Sans Souci, Kailua, Nanakuli and White Plains, which are among the 23 Oahu beaches it prioritizes as Tier 1, the state tests the water once a week. Tier 2 has 21 beaches, tested less frequently, and the 100-odd beaches in Tier 3 are tested once or twice a year. (The same system applies on Maui, Kauai and the Big Island.)

If enterococcus levels exceed the threshold, the Health Department posts no-swimming signs at the beach and advisories on the Clean Water Branch website. It also posts sewage spill and brown-water advisories.

The state does not monitor for enterococcus in brown water or at stream mouths, said Myron Honda, supervisor of the branch’s monitoring and analysis section.

In brown and stream waters, “enterococci would probably be elevated because (storm) waters wash out from the ground and enterococci grow naturally in Hawaii’s soil and streams, so it doesn’t necessarily mean it came from sewage,” Honda said. “Even in clear weather we don’t test streams because we’re very confident enterococcus is there (and) we won’t be able to determine what the source is.”

He added, “We try and discourage people, especially with little kids, from swimming in streams, because that’s where pollutants concentrate.”

But people do swim at stream mouths, so the Surf­rider Foundation tests there, said Marvin Heskett, a former board co-chairman for the group’s Oahu chapter. The nonprofit tests 20 Oahu beaches for enterococcus on one to two Sundays a month, taking conditions as it finds them, testing brown water as well as clear.

“We’re filling in where we see the need,” Heskett said.

The lab results are posted on the Blue Water Task Force website.

“We’re concerned about surfers, paddlers, swimmers and fishermen who often use these areas that aren’t a Tier 1 beach where the state tests frequently,” Heskett said.

Blue water can quickly change to brown, warned North Shore resident Tiffany Foyle, 36.

In late May, following heavy rain, she and her 6-year-old son were swimming at Waimea in clear water, away from the river mouth.

“We got out right after the water got cloudier and started to feel oily and warm, but for the next two days, our stomachs felt kind of off and we had diarrhea,” Foyle said.

They did not seek medical attention, and the cause of their distress is uncertain.

Asked about the incidence of gastrointestinal disease among ocean swimmers, Health Department spokeswoman Janice Okubo said the agency doesn’t collect this data.

Threat from cesspools

Public awareness of waterborne-illness risks has risen since winter and spring, when DOH issued advisories for high levels of enterococci at Diamond Head and Waikiki. An advisory finding 1,652/100 mL at Kuhio Beach was posted April 29 and ended May 2.

Honda said the causes remain a mystery. “We see a lot of these spikes, where it’s very high and goes down in one day, too quickly for us to do any investigation,” he said. “If it had been from a sewage spill or leak, it would be high for a longer duration.”

When high levels are found, state testers return daily until counts sink below the threshold. Spikes are “probably due to something like human or dog poop or a dirty diaper that washed in from the land at a point in time,” Honda said.

He added that the department receives complaints about homeless people defecating at beaches or by streams, but there’s no way to prove this causes high bacteria counts.

Outside of urban Hono­lulu’s challenged but improving sewer system, a more insidious source of raw sewage comes from cesspools, whose untreated contents can leach into groundwater or overflow and run off during storms.

The state has banned new cesspools and ordered that current ones be upgraded to septic systems, which filter waste, by 2050. For now, according to DOH’s wastewater website, there are approximately 88,000 cesspools in Hawaii that release a total of 53 million gallons of untreated sewage into the ground each day, posing threats to drinking water, coral reefs and oceangoers.

“We try to focus on beaches that have high cesspool concentrations in neighborhoods nearby,” said Christina Comfort, co-chairwoman of Surfrider Oahu’s Blue Water Task Force.

That includes Chocolates, a surf spot at the mouth of the Anahulu River near Haleiwa’s boat harbor, and the stream outflow at Kahaluu Park, both of which have consistently shown high enterococcus levels and lie in watersheds with high densities of cesspools, Heskett said.

Since February 2018 Surf­rider has found high levels of enterococci at Kahaluu on 21 days, including counts of 1,930/100 mL last February and 1,112/ 100 mL in April.

Surfrider’s June 30 test of Chocolates showed low bacteria (20/ 100 mL), but the site, which is popular with families as well as surfers, had high levels of 1,616/100 mL in November.

Among 14 areas statewide prioritized for cesspool remediation by DOH, five are on Oahu, with Kahaluu assigned priority level 1, and Diamond Head, Ewa, Waialua and Waimanalo assigned priority level 3.

Spotting trends

Unlike the state, which publishes only enterococci levels exceeding the threshold, the Surfrider Foundation posts all its results so beachgoers can get a sense as to whether sites trend dirty or clean.

“A lot of our sites are consistently one way or another, and you can see all of the test site’s results for the whole year,” Comfort said.

She said the nonprofit hopes to partner with the state, pooling resources. For instance, if Surfrider finds high bacteria levels, as it did at Pupukea Tidepools on May 26 when readings showed 235/100 mL, the state could do follow-up tests.

Honda said the state can’t endorse Surfrider’s results until the nonprofit files a quality-assurance document ensuring they follow state protocols.

They’re working on it, but the local Blue Water Task Force is stretched thin, said Mara Dias, national Blue Water Task Force coordinator. “It would be great for DOH to look at volunteer groups like ours as a resource, not to use our data, but to help them see areas of real concern,” Dias said.

Comfort, herself a volunteer, said the foundation needs more beachwater testers. (Email her at bwtf@oahu.surfrider.org.)

Beachwater bacteria results can be viewed on the websites of Surfrider Foundation at surfrider.org/blue-water-task-force/chapter/44 and DOH at eha-cloud.doh.hawaii.gov/cwb/#!/event/list, where one can sign up to receive emails of DOH advisories.