Safe Drinking Water Branch

The Groundwater Contamination Maps for the State of Hawaii were first published in August of 1989. Eight subsequent versions of the maps were published between 1989 and 2005. The previous editions of the maps were long in coming because of the tedious nature of developing the maps. With the application of some innovative solutions, the problems of essentially re-inventing each new set of maps has been addressed. The maps can now be more easily updated and more readily available to the public.

Where do these Maps come from?

The Groundwater Contamination Maps for the State of Hawaii are prepared by the Groundwater Protection Program, Safe Drinking Water Branch of the Hawaii Department of Health (DOH). The Maps represent current information available to the DOH and are based on monitoring data for public drinking water wells, select non-drinking water wells such as irrigation and industrial wells, and fresh water springs. Besides generating its own data, the DOH accepts data from other testing agencies such as the University of Hawaii, Hawaii Department of Agriculture, Hawaii Department of Land and Natural Resources and the U.S. Geological Survey.

What do these Maps represent?

These maps identify organic contaminants that have been detected by the Department of Health and other agencies which have reported such detections to us and confirmed through repeat testing in drinking water wells, select non-potable wells, and fresh water springs throughout the state. Organic contaminants are generally a measure of human impact on the environment as they are not generally naturally occurring in the environment. Contaminants may come from herbicides, pesticides, industrial solvents, fuels and other sources which are applied, spilled, leaked or disposed of into the ground. Groundwater contamination is an especially significant concern in Hawaii because nearly all of Hawaii’s drinking water comes from groundwater sources.

The intent of these Maps is to identify only those wells with detectable levels of groundwater contamination. We are striving to report actual groundwater contamination and therefore are attempting to report the quality of the water directly out of the ground prior to any treatment to remove contaminants. We also do not include naturally occurring contaminants. Just because a source does not appear on these maps does not mean it is not contaminated. Some contaminated wells may not be listed because they have not been reported due to of lack of confirmed data, or the wells may not have been tested. The contamination levels in this document refer to reported levels of contamination on a specific sampling date. Levels of groundwater contamination may fluctuate for a number of reasons, including actual diminishing or increasing levels of contamination, chemical breakdown of contaminants, variability in sampling and analytical methods, the effects of pumping rates, and other factors. Groundwater sources previously reported as contaminated whose latest test resulted in a “not detected” or “ND” report are no longer included in this report. Some data are extremely old because of the inaccessibility of the source or lack of resources to perform resampling.

What do these Maps tell us?

The Maps show that groundwater contamination continues to occur in Hawaii. Our knowledge base concerning chemicals continues to grow about the contamination potential of many chemicals, their behavior as they travel down the soil column, their degradation or lack of degradation, the mechanisms that serve to promote or restrict groundwater contamination and much more. Today, many activities strive to prevent groundwater contamination through regulation and clean-up requirements, however, contamination initiated years ago prior to these activities may just now be showing up in our groundwater. Further the use of new and innovative chemicals will continue to challenge our groundwater protection efforts.

Is the water safe?

This version of the Groundwater Contamination Maps includes a “Glossary” which includes health effects language from the state and federal regulations or information on lifetime health advisories and the one in ten thousand (10-4) cancer risk levels where standards have not yet been established. For those contaminants with an MCL or SMCL, as long as the detected level is below the MCL or SMCL, the water is considered safe. The DOH will also use the lifetime health advisories and the cancer risk levels to determine the safety of the water. Please keep in mind that at least for drinking water sources, there may already be a treatment facility to remove groundwater contaminants.

More information about the map and groundwater protection is available from the Department of Health, Safe Drinking Water Branch, Groundwater Protection Program. Click here to open the application.

Hawaii Department of Health
Environmental Management Division
Safe Drinking Water Branch
2385 Waimano Home Road
Pearl City, Hawaii 96782-1900
Phone: (808) 586-4258
Fax: (808) 586-4351
Email: [email protected]