Water Quality FAQ

The Honolulu Board of Water Supply (BWS) works hard to ensure that the water served to our customers meets or exceeds all federal and state safe drinking water standards and we want to reassure you that the water we deliver to you is safe to drink. Here are some commonly asked questions.

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General FAQ

What are the Drinking Water Standards?

The Safe Drinking Water Act (SDWA) is the federal law that governs the quality of drinking water in the United States. Under the SDWA, the U.S. Environmental Protection Agency (EPA) sets standards for drinking water quality and oversees state compliance with those standards.

In Hawaii, the State Department of Health (DOH) is responsible for ensuring that all public and private drinking water suppliers comply with state and federal drinking water standards. The ultimate responsibility rests with each water supplier to comply with the standards. The DOH and EPA are responsible for monitoring and enforcing these regulations.

Does the BWS test the water?

Yes. Every year, the BWS conducts thousands of tests on the water source and distribution system to ensure that the water you receive is safe to drink. These tests check for 91 different types of contaminants, as required by the EPA. All final test results show the BWS is in full compliance with State and Federal standards for safe drinking water. If the water quality tests conducted did not meet State and/or Federal safe drinking water standards, the BWS would be required by law to immediately notify impacted customers and more importantly, the BWS would stop serving that water until it meets all State and Federal drinking water regulations.

Does the BWS treat the water?

Yes, the BWS treats water in accordance with all State and Federal drinking water regulations. Currently, the BWS treats drinking water with chlorine, and in certain areas of Oahu the water is also treated with granular activated carbon (GAC).

How can I find out what is in my water?

Water quality test results are shared with our customers in our annual water quality report or Consumer Confidence Report (CCR), as required by the EPA. The CCR, along with an accompanying water quality informational pamphlet, will be mailed to you by July 1 each year. The CCR identifies where your water comes from, what regulated contaminants were found, how those levels compare to the standards for safe drinking water, and describes any treatment processes used. To get your water quality report or the water quality informational pamphlet, please visit http://www.boardofwatersupply.com/water-quality/water-quality-report.

Is all of our drinking water on Oahu chlorinated?

Yes, all of the water pumped into the BWS water distribution system is chlorinated.  Concentrations ranging from 0.25 to 0.5 milligrams per liter (ppm) of chlorine can be found throughout the water system.  Since excessive amounts of chlorine can affect the taste and odor of drinking water, the BWS adds only what is needed to keep disease-causing bacteria from contaminating our water supply.

If you experience a strong chlorine smell or taste in your water, contact the BWS Microbiological Laboratory at (808) 748-5850.

Is fluoride added to the drinking water on Oahu?

The BWS does not add fluoride to the municipal water supply. However, military installations add both fluoride and chlorine to their water supplies regardless of water quality.

Is there lead in our water supply?

In accordance with federal and state regulations, the BWS tests for lead in water samples taken from consumers' household taps. Based on these tests, our water supply meets the standard for lead in drinking water.

What is the pH of our water?

pH refers to the acidity or alkalinity of water and is expressed in terms of a numerical scale from 0 to 14. Seven (7) on this scale means that the water is neither acidic nor alkaline. For values less than 7, the smaller the number, the more acidic it is. For values greater than 7, the larger the number, the more alkaline it is.

The pH balance of the drinking water served by the BWS occurs naturally in the 7 to 8 range. This means that the water ranges from being neither acidic nor alkaline (pH 7) to being only slightly alkaline (pH 8).

Does the BWS conduct free tap water tests?

The BWS conducts tests at the tap only when specific water complaints—such as taste, discoloration, odor, or presence of particulate matter—are received from our customers.

If customers are curious about what is in their water, they should contact a private laboratory to have a sample analyzed. These laboratories are listed in the telephone directories under Laboratories-Analytical or can be found through a keyword search on any online search engine.

Do customers need to purchase water filter units for their homes?

The municipal water supply served to Oahu's residents is safe to drink and use, and does not require treatment by a home filtration unit.

Does the BWS offer consumer guides to home filtration systems?

The BWS does not offer any information or consumer guides on filtration systems. Customers should conduct their own research about water filter products when making a decision on whether to purchase such a system or device.

In incidents of water quality complaints, the BWS will not test water that has been altered by the installation of a filtration system. The customer may need to contact a private laboratory to have a sample analyzed, or check with the product representative or manufacturer for assistance.

Guidance for Large Buildings

I'm reopening my building, which has been closed, with little to no water use, for an extended period of time. What do I need to do?

Large buildings planning to reopen for business should follow the Centers for Disease Control and Prevention (CDC) guidelines for flushing water lines at facilities where there has been low to no water use.

Additional Resources:

Red Hill Bulk Fuel Storage Facility FAQ

Why is the Board of Water Supply (BWS) so concerned about the Red Hill Bulk Fuel Storage Facility?

The Red Hill Bulk Fuel Facility continuously stores 187 million gallons of fuel in 70+ year-old tanks that are located just 100 feet above a State designated drinking water aquifer. The BWS uses water from this aquifer to serve residents from Moanalua to Hawaii Kai. Navy studies show the groundwater underneath and within close proximity to the tanks is already contaminated with petroleum chemicals. These studies also document leaks dating back to 1947, continuing corrosion of the tank liners, and the risk of a large catastrophic fuel release. If such a release occurred, it could pollute the aquifer and our water supply for many years.

See News & Updates on Red Hill >

Why should I be concerned about Red Hill? I don't live near Red Hill or get water from wells in this area.

The situation at Red Hill poses a threat to existing BWS wells that are presently not contaminated. If these wells ever became contaminated, for instance by a catastrophic, large volume release from Red Hill, then water rates would need to increase to pay for treatment to remove the contaminants from the water. If the situation involved a very large release, the cost to treat could become prohibitively expensive as to render the wells and aquifer unusable for decades to come. In the event this occurred, existing BWS wells unaffected by the incident do not have the capacity to make up the difference, resulting in long-term water moratoriums. Water rates would need to increase to pay for alternatives to take the place of the water loss. Since water rates apply to all BWS customers island wide, everyone would end up paying for what happens at Red Hill.

See News & Updates on Red Hill >

How could the wells be contaminated by a fuel leak?

Fuel from the tanks that leak into the groundwater can eventually spread to neighboring wells because the groundwater is always moving. The amount of fuel contamination in the aquifer and how quickly it spreads depends on the volume of fuel released into the groundwater. A large volume of fuel released into the groundwater due to a major pipe or tank failure will contaminate the groundwater much faster, in greater amounts and over a larger area than fuel that is slowly leaking from the tanks.

See News & Updates on Red Hill >

Are the BWS wells showing signs of contamination?

Not at this time. However, Navy studies show contamination is present in the groundwater underneath the tanks. This contamination can move in the groundwater and spread to neighboring wells in the area.

See News & Updates on Red Hill >

What contaminants are being found in the groundwater and wells?

Petroleum hydrocarbons and various related chemicals such as, total petroleum hydrocarbons as diesel (also called TPH-d), naphthalene, 1- methylnaphthalene, 2-methylnaphthalene, toluene, benzene and lead.

See News & Updates on Red Hill >

What would a worst case scenario look like?

A catastrophic fuel release could occur as the result of structural failure of the tanks caused by an earthquake. This could result in more than a million gallons of fuel released into the groundwater and potentially several million gallons to Halawa Stream and Pearl Harbor.

See News & Updates on Red Hill >

In such a scenario, what actions would the BWS take?

The BWS would immediately shut down our Halawa Shaft and Moanalua Wells. The BWS would then impose a water moratorium in Honolulu. The Navy's Red Hill Shaft would also be shut down, creating a water shortage for Pearl Harbor. A large fuel leak would render the groundwater aquifer unfit for drinking for decades as treatment alternatives in such a scenario would be ineffective and costly.

See News & Updates on Red Hill >

What is the BWS asking of the Navy?

To protect the aquifer's long-term ability to provide safe drinking water, the BWS urges the Navy, EPA, and Hawaii Department of Health (DOH) to:

  • double line the Red Hill tanks. If not, then relocate the tanks away from the potable water aquifer;
  • meet the same EPA and DOH regulatory requirements imposed on all other Underground Storage Tanks; and,
  • • clean up the fuel that is already underneath the tanks to reduce the long-term threat to other wells in the area.

See News & Updates on Red Hill >

Are the tanks still leaking jet fuel?

Many leaks have occurred in the past, and the most recent in January 2014. Tank tightness tests currently performed annually by the Navy cannot rule out the presence of any slow chronic leaks that may be occurring below the test’s ability to measure. Slow leaks can release up to 4,400 gallons of fuel per year per tank. Groundwater testing conducted by the Navy since 2005 continue to show petroleum contaminants present in the groundwater underneath Red Hill at levels that, in one case, has exceeded Hawaii DOH environmental action limits. This contamination could have been caused by the 2014 reported leak, earlier leaks, or more recent unreported leaks. Navy studies also show rusting is occurring on the backside of the tanks that can lead to through wall corrosion producing a tank leak. If the Navy continues its standard practices, the rusting will continue and likely lead to more frequent and larger leaks in the future.

See News & Updates on Red Hill >

Does the BWS have underground storage tank enforcement powers when it comes to protecting Oahu's water sources?

No. The Hawaii DOH has jurisdiction and regulates underground fuel tanks in Hawaii.

See News & Updates on Red Hill >

What are the health effects of these chemicals in our water?

In 2016 BWS contracted toxicology experts to determine the health significance of low-level petroleum chemicals in drinking water and their health effects. The study determined that levels below 100 parts per billion (ppb) [same as micrograms per liter] of total petroleum hydrocarbons as diesel (TPH-d) in water is safe and protective of public health. Consuming water containing TPH-d levels at or below 100 ppb is not expected to produce toxic effects. Research studies show the health effects of high levels of TPH-d can cause changes in red blood cell counts and noncancerous liver and kidney changes. Based on these results, BWS strongly urges clean-up of the groundwater underneath and surrounding the Red Hill tanks and to use 100 ppb as the minimum clean-up level. This 100 ppb level is also a taste and odor threshold and environmental action level (EAL) established by DOH.

See News & Updates on Red Hill >

Are there any national environmental standards for underground fuel storage tanks?

Yes. There are federal and state regulations that apply to all underground storage tanks. However, Red Hill is a field-constructed underground tank system that had been deferred from many of the requirements that must be met by smaller facilities. In 2015, the EPA revised the underground storage tank regulations. Unfortunately, the revised rules still exempt field constructed tanks like Red Hill from the regulatory requirements that must be met by all other underground storage tanks.

See News & Updates on Red Hill >

What can residents do to support the BWS in this endeavor?

Help the BWS to keep our drinking water safe by staying informed and doing your part to keep this issue top of mind.

  • READ THE AOC & SOW for the Red Hill project: www.epa.gov/red-hill/red-hill-administrative-order-consent
  • STAY CURRENT on news and updates about Red Hill on the BWS, EPA and DOH websites.
  • ATTEND PUBLIC MEETINGS about issues related to Red Hill. 
  • VOICE YOUR CONCERNS about protecting our groundwater resources.
  • SHARE UPDATES about Red Hill and initiatives to protect Oahu's drinking water family and friends.
  • CONTACT YOUR ELECTED OFFICIALS and let them know you are concerned about Red Hill and that you support efforts to protect Oahu’s groundwater resources.

See News & Updates on Red Hill >

Who are the project coordinators for Red Hill?

Contact information for the project coordinators for the Hawaii State Department of Health (DOH), U.S. Environmental Protection Agency (EPA), and the U.S. Navy can be found here.

See News & Updates on Red Hill >

Chromium VI FAQ

Does the BWS test for hexavalent chromium in the water supply?

Yes. In compliance with the EPA Third Unregulated Contaminant Monitoring Rule (UCMR3), the Board of Water Supply (BWS) tested Oahu's water supply for hexavalent chromium. All results are reported in the BWS consumer confidence report (CCR) as required by the UCMR3 regulation and are within the DOH’s action limit of 13 parts per billion (ppb). Since completing the UCMR3 testing requirements, BWS has elected to conduct annual testing of its water sources for hexavalent chromium. Action limits or health advisories is an estimate of acceptable drinking water levels for a chemical substance based on health effects information. It is not a legally enforceable standard. The EPA presently has no maximum contaminant level (MCL) in drinking water for hexavalent chromium citing the present total chromium MCL as protective of human health.

Does the BWS have a MCL for hexavalent chromium for Oahu?

MCLs are established by regulatory agencies with environmental and public health risk assessment expertise such as EPA and the DOH and not BWS. These MCLs govern the quality of water supplies delivered by utilities like the BWS. The BWS is constantly in contact with federal and state regulatory agencies and national water associations to ensure we stay abreast of issues related to the safety and quality of our water supplies.

Does the BWS have a MCL for total chromium, which would include hexavalent chromium and trivalent chromium?

The BWS monitors its water supplies in compliance with the present EPA MCL of 100 ppb for total chromium. The results show our sources presently meet the current MCL for total chromium and are available on our Consumer Confidence Report (CCR), which we provide to all customers each year. Customers can access the CCRs for their areas online at http://www.boardofwatersupply.com/water-quality/water-quality-report.

Can the BWS test my water for hexavalent chromium?

The BWS does not perform individual testing for hexavalent chromium. If you would like to have your water tested for hexavalent chromium, please contact a private laboratory.

California became the first U.S. state to have an MCL specifically for hexavalent chromium of 10 ppb. Is this a reasonable level for drinking water?

The BWS is not a public health agency and therefore not in a position to comment on California's MCL. We recommend visiting the California State Water Resources Control Board website for more information on California's hexavalent chromium MCL.

What would be the likely source of hexavalent chromium in drinking water?

According to the EPA, chromium naturally occurs in rocks, animals, plants, soil, and in volcanic dust and gases. Water sources can be affected by hexavalent chromium naturally, or through contamination plumes from industrial centers, landfills, and improper discharge of industrial processing streams. For more information, visit the EPA's website at http://www.epa.gov/.

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Updated: 05/29/2020