Source Protection

Protect Your Drinking Water, Protect the Source

What you do in and around your home or business can affect the quality of your water. Whether you are cleaning your home, maintaining your yard, or changing the oil in your car, there are several important ways you can help prevent pollution by adopting Best Management Practices for your Business, Farm, or at Home.

Find Your Water Source

The Maui Department of Water Supply serves five main sections within the County: 

  • Central Maui
  • East Maui
  • Molokai
  • Upcountry Maui
  • West Maui

The system with the most customers is the Central system, which includes Wailuku, Paia, Kahului, and Kihei. The next largest system is the Upcountry water system, which is actually the largest geographically. This includes Kula, Pukalani, Makawao, and Haiku. Lahaina is third, then Molokai, and then Hana. Water on the island of Lanai is provided by a private company. Click the link to find your water source and other information about where it comes from.

Value of Safe Drinking Water

70% of our community relies on groundwater for our drinking water needs. The following are the economic benefits of source protection to a community:

  • Achieve better chemical management (for businesses) and thereby reduce liability
  • Avoid the cost of well replacement due to contamination
  • Avoid costly treatment systems to treat contaminated drinking water
  • Avoid remediation costs required to remove a source of contamination

Potential Threats

Land uses that are considered potential contaminating activities are those facilities that typically use, produce, or store contaminants, which, if managed improperly, could find their way to a drinking water source. Contaminants such as pathogens, oils, and toxic chemical compounds can reach your water supply through direct discharges above and below the land surface and through stormwater leachate and runoff.

Drinking water wells can become contaminated by activities such as dumping motor oil or household chemicals on the ground, pesticide applications, chemical leaks or spills.

Potential Groundwater Contamination Sources Poster


Areas That Re-Charge Our Wells

The land areas that could contribute water and pollutants to the ground water below are delineated, or mapped. These Wellhead Protection Areas are the surface and subsurface areas surrounding a water well through which contaminants can move toward and reach such water wells.

Wellhead Protection Overlay Zones

Wellhead Protection Overlay Zones were delineated for purposes of safeguarding ground waters that supply, or potentially supply, drinking water to wells operated by the Department of Water Supply. The Wellhead Protection Overlay Zones are divided into Zone B and Zone C based on the time it takes a drop of water to travel to the drinking water well. In Zone B it takes 2 years or less and in Zone C it takes up to 10 years travel time.

Maui County Wellhead Protection Program

The Department of Water Supply initiated the Wellhead Protection Program to protect the wells that supply drinking water to our community. Department staff identified activities that have the potential to contaminate groundwater. The Department is working with landowners and stakeholders to develop and implement protection measures in delineated Wellhead Protection Areas. Protection strategies and a Draft Wellhead Protection Ordinance were developed with community input at ten public meetings throughout Maui County.

For more information about this program, contact the Water Resources and Planning Division at (808) 463-3110.

Draft Wellhead Protection Overlay District Zones for Department of Water Supply Wells

Map of the Islands