Water service could be impacted by potential Public Safety Power Shutoff as Hawaiian Electric continues to monitor wildfire risk

Hawai‘i County Department of Water Supply reminds the public that water service could be impacted if power is disrupted or turned off pre-emptively as a fire-safety response to high winds and dry conditions while Hawaiian Electric continues to monitor the risk of wildfire in areas of the Big Island with the highest exposure of flames igniting.

Hawaiian Electric said at 4:30 p.m. today (July 8) that its Public Safety Power Shutoff Program will remain at “watch” level into Wednesday as it keeps a close eye on weather conditions in Maui and Hawaiʻi counties.

The electric utility urges customers in those high-exposure Public Safety Power Shutoff areas to review their own emergency plans and prepare for the possibility of extended power outages.

Hawai‘i County Department of Water Supply relies on Hawaiian Electric power to operate county wells and booster pumps to distribute water to its customers.

If there were the possibility of a proactive power shutoff, customers in those high wildfire exposure areas affected would be asked to reduce water usage so the department could adjust systems and resources in preparation for any necessary fire protection.

“Our understanding is that a [Public Safety Power Shutoff] outage could last hours to days, depending on weather conditions, location and extent of damage,” a county Department of Water Supply release said. “An extended power outage could diminish or deplete portions of [Department of Water Supply’s] water systems and leave customers with low pressure or no water.”

If Hawaiian Electric implements a proactive power shutoff, the water department will likely need to restrict or ration potable water for fire protection, drinking, cooking and personal hygiene purposes only.

Car washing, irrigation and other non-essential uses of water would need to be suspended until all power and water systems are returned to normal.

Hawai‘i County Department of Water Supply uses backup electrical generators at a limited number of well sites, but these emergency generators cannot fully replicate the Hawaiian Electric power grid.

Customers and anyone who depends on a continuous supply of Department of Water Supply water also are urged to review their personal situations and prepare accordingly in the event of any prolonged power outage that disrupts water service.

They should have alternate sources of potable water and enough supply to meet essential needs.

Ways to safely store drinking water are listed in the “Water Emergency Preparedness” guide available under the “Community” menu on the water department website.

Any messages regarding weather conditions and potential impact of any future power outages on water customers — should they be necessary — will be issued by Hawai‘i County Department of Water Supply or Hawai‘i County Civil Defense.

Call the department at 808-961-8050 during normal business hours for questions, concerns or information. Call 808-961-8790 for after-hour emergencies. You can also email to dws@hawaiidws.org.

Hawaiian Electric reminds customers in high-risk wildfire areas there are three criteria that must be met before a Public Safety Power Shutoff is initiated:

• Persistent drought conditions.
• Wind gusts 45 mph and higher.
• Relative humidity below 45%.

Data from weather stations and cameras near the utility’s infrastructure in high-risk areas is used to determine whether a shutoff might be necessary with potential for fire spread. Wind gust readings near electrical infrastructure could be higher than in residential areas.

Any current outages are not related to the Public Safety Power Shutoff Program.

Visit the Hawaiian Electric website or call Hawaiian Electric’s toll-free Public Safety Power Shutoff hotline at 1-844-483-8666 for more information and maps of areas with have high wildfire risk.

National Weather Service forecasters in Honolulu allowed the wind advisory that was in effect for north, northwest, south and southeast portions of the Big Island as well as the summits of Mauna Kea and Mauna Loa to expire on time today as gusty trades continued to weaken.

However, the latest area forecast dicussion said there could still be some isolated advisory winds in the most wind prone areas tonight.

Dry conditions will combine with those continued strong gusty winds to keep fire danger elevated, mainly over drier leeward slopes.

As a high pressure ridge north of the state weakens, change blows in tonight into Wednesday as those strong winds gradually weaken overnight, ushering in moderate to breezy trades for the rest of the week and a return toward typical summertime trade wind weather.