Oahu’s municipal drinking water is provided by groundwater sources, which are dependent on recharge from rainfall. Groundwater sources are less susceptible to drought and climate variability. The Board of Water Supply (BWS) continuously monitors rainfall and groundwater levels to ensure the island's drinking water supply is preserved.

If we each save a little, together we save a lot.
While brushing your teeth, fill a cup of water to rinse your mouth and turn off the tap.
7 Easy Ways to Save Water, Save Money
1. Water lawns just 2-3 times per week
2. Don't water lawns between 9 a.m. and 5 p.m.
3. Check for leaks in plumbing and toilets
4. Install water-efficient plumbing fixtures
5. Take shorter showers
6. Put a nozzle on your garden hose
7. Don't let the faucet run and run

Oahu Groundwater Levels

The BWS maintains wells across the island to track the health of the aquifers from the effects of varying rainfall and pumping trends. During hot summer months, when rainfall is low and water demand is high, water levels decrease. If water levels drop too low, the source could be harmed, with long-term detrimental impacts. Monitoring low groundwater levels allows the BWS to adjust pumping operations and inform the public that summer water conservation is necessary. 

save water for life water toastWe remind ALL Oahu water customers to please use water efficiently and to not waste it. If we each save a little water, together we will save a lot and ensure water supplies are sustainable for generations to come.

See senseless water waste?
Call the Water Waste Hotline at (808) 748-5041.

Why conserve water? Here are some good reasons:

  • It is a finite resource.
  • Protect the health of the aquifer.
  • Save energy and reduce your carbon footprint.
  • Reduce need/costs for the BWS to develop additional sources to meet demand.
  • Promote sustainability of the resource for future users.

BWS Resources

Other Resources


Water Levels Status Reports


For More Information

Contact the BWS Communications Office at (808) 748-5041 or at contactus@hbws.org.