Water departments on Oʻahu and Hawaiʻi Island have advised customers to conserve water ahead of possible storm-related power outages this month.
But what does the power grid have to do with the water supply?
It is impossible to separate Hawaiʻi's power system from its water system, said Kawika Uyehara, deputy director of Hawaiʻi County's Department of Water Supply.
On Hawaiʻi Island, "water systems rely pretty much 100% on Hawaiian Electric’s grid power," Uyehara said.
Without electricity, the water utility can't pump water out of the ground. The tap won't run dry the minute the power goes out, but given enough time, customers might face a water shortage.
"Anything over six to eight hours of no power, then we start to get more concerned about our water delivery capabilities," Uyehara said.
Exactly how long a customer will have water depends on where they live. During a blackout, customers can still access water stored in the department's water tanks.
That supply could last up to a week if few people are tapped into that water tank, Uyehara said.
But in densely populated areas on Big Island like Kona, Hilo and Waimea, Uyehara said the water supply in the tanks may last less than a day.
Likewise, Honolulu Board of Water Supply Kathleen Pahinui said Oʻahu has "about a 24-hour supply in the reservoir from the time that the power goes out to the time that it could conceivably run dry."
BWS has an emergency plan to ensure continued water access to critical infrastructure. Additionally, hospitals have backup systems in place like generators and energy storage. Pahinui noted that the Queen's Medical Center even has its own water wells.
Still, Pahinui said that any kind of outage presents challenges, be it a result of bad weather or a rolling blackout. Hawaiʻi Island and Oʻahu have experienced their share of both in the past few weeks.
"Anytime there's a power outage, it's not just 'We can just go back in and flip a switch and turn our pumps back on,'" Pahinui said.
Pahinui said that pumps have to be turned on carefully and in a specific sequence to avoid pressure surges that could cause main breaks in the water line.
This process requires careful coordination between water departments and Hawaiian Electric. And now, new wildfire protocols have thrown other considerations into the mix.
HECO spokesperson Darren Pai said that in areas at high risk of wildfire, the utility will take additional steps before restoring power to downed lines.
"In those cases, it is possible that the power may stay off, because it may be necessary to go out and conduct visual inspections of those power lines to ensure that there's nothing that's still caught in the lines that could spark," Pai said.
The utility is also exploring the implementation of a Public Safety Power Shutoff Program, Pai said, under which the utility would shut off the power proactively in high-risk areas during wildfire weather conditions.
For that to work safely and successfully, Pai said everyone needs to be on the same page — including water providers.
Pahinui confirmed that the Board of Water Supply is in talks with HECO about these programs.
"We don't ever stop thinking about this," Pahinui said. "The wildfires were horrible, and really opened everybody's eyes in a whole new direction that I don't think most of us had ever thought about."
