Sadly, it happens almost like clockwork. The heavy rains hit; the sewage flows into our ocean waters. In just one of the many spills last Friday, more than 100,000 gallons of untreated waste spilled into the waters off Kane'ohe.

In a state dependent on tourism, tourists taking a dip in dirty water, unaware of the posted warning signs indicating dangerous levels of bacteria from the sewage overflow, is not the image we want to leave with visitors.

The city has already been forced to embark on a multi-year sewage system worth billions of dollars, with oversight by both the state Department of Health and the U.S. Environmental Protection Agency. Indeed, Mayor Mufi Hannemann inherited a woefully neglected sewer system and has been working to catch up.

Still, despite some improvements, spills do occur that require state health warnings.

Larry Lau, the Department of Health's deputy director of environmental health, said steps were taken to ensure that during the EPA revamping project, heavy rains didn't force sewage to run off into the ocean. The sanitary system and the runoff are separate and shouldn't mix, he said.

But last week's rains have resulted in at least five spills, bringing the total on O'ahu to 18 since the rainy season began in earnest late February.

Lau said his department also needs to do a better job of warning people. "Not everyone on the beach gets the message," he said.

Beyond the warnings, residents and tourists alike deserve clean ocean waters. These chronic overflows of raw sewage into our ocean are indeed an unconscionable way to treat our environment.