Honolulu is studying the possibility of establishing a stormwater utility to ensure the island’s aquifers are prepared for a future of drought, increased development and a growing population.

Aquifers are bodies of rock or sediment that hold groundwater and are the sources of nearly all the fresh water in Hawaii. The city said that more can be done to make sure that stormwater gets soaked back into the ground to recharge those aquifers rather than being directed into storm drains and into streams and rivers.

“We’re hoping to implement programs that will incentivize people to capture and reuse stormwater on their property and not just develop property to push the stormwater off into the street and into the storm drain system where it will ultimately end up in a stream or river and then into the ocean,” said Ross Sasamura, director of the city’s Department of Facility Maintenance.

For property owners, that could mean simply diverting rainwater onto lawns or gardens but also could mean establishing catchment systems.

The counties in Hawaii were given the authority to establish such a utility in 2015, and Honolulu has been gathering preliminary data since then.

The city said in a news release Monday that it will begin collecting public input as it considers the kinds of services that will be provided by the utility as well as a fee structure that would be applied to all property owners.

Sasamura did not provide an estimated fee if the utility is established, but a nationwide survey published by Western Kentucky University last year showed that the average monthly residential fee for a single family was $5.85, while the median fee was $4.75.

Though water shortages are not of particular concern in Hawaii now, a combination of climate change and increasing development likely will make them a problem in the coming decades.

“We are looking at the very beginning of the impacts of climate change,” said Chip Fletcher, associate dean for academic affairs and a professor at the University of Hawaii’s School of Ocean and Earth Science and Technology. “A stormwater system that would catch the gift from the sky … I think is the very first thing we want to do in terms of building sustainability on this island.”

Sasamura said more intense periods of drought could come in 40 to 50 years. Fletcher said it is difficult to say when water resource problems will become more dire but that preparing for them needs to start now.

“Starting now is exactly the time to start on this issue … to implement a new recognition of the true value of water on an island that has to be sustainable,” Fletcher said. “We can’t call across the state line and ask California … to borrow some of (their) reservoir water. We are truly isolated here when it comes to drinking water.”

In Hawaii the average annual rainfall has decreased an average of nearly 1.8% per decade during the last century or so, according to the Pacific Islands Climate Science Center. Fletcher said it has been 6% over the last 30 years.

The utility would be for water security, but it would also involve limiting pollutants from entering storm drains, streams and the ocean. Sasamura said Honolulu spends $90 million per year in “stormwater management.”

He said that cost is derived from a wide range of work being done by many employees across the city that can be as simple as properly disposing of grass clippings at parks or picking up trash along with services provided by street sweepers.