Is Hawaii Tap Water Safe To Drink ?

One of the most common questions I get from visitors is this: Should I buy bottled water or drink the tap water when I visit Hawaii?

The short answer is: Yes.

According to the Board of Water Supply, Hawaii tap water is some of the best quality drinking water around. It is rainwater that is naturally filtered through underground porous volcanic rock for about 25 years before it reaches aquifers.

“It is very pure and requires very little treatment,” Erwin Kawata, the Honolulu Board of Water Supply’s Water Quality Division program administrator told Civil Beat.

Kawata told the online news source, Civil Beat, “There is almost no bacteria in the water in Hawaii, which is why the chlorine which has to be put into the water here is very low compared to other cities.” Very low means zero to 0.15 milligrams per liter.

In fact, if you buy bottled water on Oahu, it’s very likely the exact same water you would find if you filled your bottle from the sink in your hotel. That’s because bottled water for sale on Oahu comes from the same aquifers as our tap water.

Kawata says that many mainland cities use surface water from rivers and lakes — water that is exposed to contaminants in the air. But, Hawaii’s water, which percolates through basalt below the ground, is protected from airborne bacteria.

Hawaii tap water is rainwater that is naturally filtered through underground porous volcanic rock for about 25 years before it reaches aquifers.


Yet in spite of all the scientific evidence and the regular testing of all municipal water in Hawaii, there is a subtle effort by some water treatment companies and bottled water manufacturers to make us feel uncomfortable about the water from islands’ taps.

And, to be fair, many visitors to Hawaii live in places where the tap water ISN’T safe. So, it makes sense to feel skeptical.

If you still want to buy bottled water while on vacation in Hawaii, you might see the name brand, Menehune. Menehune is the state’s biggest bottled water company.

Joseph Hartzman, the company’s director of sales and marketing told Civil Beat that Menehune’s bottled water is from the same aquifer as regular tap water but that it has been filtered in an eight-step reverse osmosis process that removes 99 percent of the water’s minerals.

In reverse osmosis, dissolved inorganic solids are removed from water by using pressure to push the water through a semi-permeable membrane. The membrane allows the water to push through but not the dissolved solids, which are flushed down the drain.

Tap water in Hawaii is not only safe to drink, but it's just as safe to drink as bottled water.

Hartzman told Civil Beat that demineralized water “assimilates into our bodies a lot quicker than when minerals are blocking the way.”

But, according to the online news source, there is no scientific proof reverse osmosis makes water assimilation speedier or that demineralized water is healthier.

Kawata of the Honolulu Board of Water Supply told Civil Beat that, even if the science to back up companies’ claims that reverse osmosis water is healthier is non-existent, “if people feel more comfortable drinking it, it’s their choice. It’s a personal matter.”

According to Civil Beat, all water in Hawaii is treated with chlorine and in some areas the water is routinely treated with granular activated carbon.

Each year the Board of Water Supply and the Department of Health conduct thousands of tests on drinking water as required for all states by the U.S. Environmental Protection Department. Kawata says by federal and state law, water cannot be served unless it is safe.

Bottom line? Hawaii tap water IS safe to drink. And, it’s no less-safe than bottled water, most of which comes from the same place as our tap water. So, drink up and feel good about it!