Not A Drop To Drink: Despite Technological Improvements In Rainwater Catchment Systems, Many Hawaii Residents Don’t Have Potable Water In Their Homes
by Bryan T. Silverman
PAHOA, Hawaii — For a region that boasts more than 100 inches of rain per year, it’s quite paradoxical that Hawaii Island’s Puna district highlights the state’s many problems surrounding water insufficiency. Despite the abundance of water in Puna, the lack of county water lines combined with no statewide standards for rainwater harvesting systems pose unique and often overlooked problems for the region.
Most of Puna rests on the eastern flank of the Kilauea volcano, and is home to the highest concentration of residential rainwater catchment systems in the United States, not so much out of preference but because the rocky volcanic terrain in this area makes the feasibility of installing water utility lines expensive and physically difficult. Harvesting rainwater as it drops out of the sky for household use sounds like it makes sense in a place that receives so much of it, and the rain gets even more abundant as you go farther up the mountain. But getting your water for free comes at a price, not always measured in dollars but in the water quality itself. Despite such reliance on water catchment systems, many of them on Hawaii Island fall short of providing potable water for their end users.
For the other Hawaiian islands, reliance on water catchment systems is less common. On the mainland, rainwater harvesting has long been a rarity, and is even banned outright in some jurisdictions. With rising utility costs and concerns about the impacts of climate change, however, water catchment is increasingly seen as a viable alternative to dependence on municipal water systems, to the occasional ire of utility companies and regulatory bodies. But harvesting rainwater is not as simple as it sounds. With increased interest in the practice, there is also a high potential for coinciding increases in waterborne illnesses.
Missing Data and Misinformation
Water catchment in the state of Hawaii is not regulated at all, not even at county or municipal levels. Hawaii residents who use water catchment systems are truly all on their own. For better or worse, this lack of regulation has created a patchwork not only of system setups but also ideas about the best practices for system maintenance, filtration, roofing materials, and water treatment protocols. Some of these are going to be better than others, even if the worse ones are more common.
Data on water catchment systems are spotty at best. According to a rainwater harvesting guide written by Patricia Macomber, first published in 2016 by the College of Tropical Agriculture and Human Resources, University of Hawaii At Manoa, it is estimated that between 30,000 and 60,000 people in the entire state of Hawaii are dependent on rainwater harvesting for household water needs, most of whom are located on the Big Island. This number is expected to grow as new home construction has seen an uptick in the Puna district, one of the last affordable housing markets in the state, where homes can sell for hundreds of thousands of dollars less than Hawaii’s median list price of $780,000, according to real estate website Redfin.
As real estate demand increases, so does the demand for rainwater harvesting systems. Many of these systems are not suitable for delivering potable drinking water, even if they’re new. Buyers moving to Puna from other islands and the mainland unfamiliar with water catchment often do not know that stock systems installed by homebuilders could make them ill, corrode their pipes over time, and expose them to harmful pathogens and heavy metals. But this lack of knowledge isn’t just limited to newcomers.
Todd Lolla, known professionally as Uncle Tilo, and Kathy Archer run a water catchment business in Pahoa. Uncle Tilo’s Clean Water provides whole-house filtration systems, various types of filters, water mineral packs, and even a free water education class open to the public on the first Saturday of every month in the parking lot just outside the storefront.
“There is a lot of misinformation that has just been introduced over the years that it’s tough to get rid of,” Uncle Tilo said. “One of the biggest hindrances we find in our rainwater harvesting community is there are a lot of people that have been here for 20, 30 years that are stuck in that time era, where at the time it was like yep you catch the water, you run it through a filter, you drink it, that’s it.”
Harvesting rainwater for potable use is a bit more involved than the protocol Uncle Tilo rightfully derides. Running water through a single string filter and piping it into your house might block most of the coarse sediment and some of the gunk that gets trapped in gutter downspouts, but this setup does nothing to prevent pathogens and parasites from making their way into the water supply.
“Right now, people in Hawaii are way behind. Australia is way ahead of us. Even India that uses a lot of rainwater, if you told them you were going to put in a catchment system with no pre-filter in India, they would look at you and say you can’t do that, it has to have a pre-filter, it’s not even a question anymore,” he said.
For the sake of example, the whole-house filtration system Uncle Tilo’s provides uses a 20-micron sediment filter, a 5-micron coconut-shell carbon-block filter, and an ionizing filter containing ceramic beads that are coated with titanium dioxide and silver. While this isn’t the only possible setup for bringing household catchment water up to a potable standard, it is notable for not needing any electricity, as opposed to other systems that use an ultraviolet (UV) light in lieu of an ionizing filter as the last line of defense before the rainwater is pumped through a home’s plumbing system.
“It doesn’t help either that one of [our] competitors tells people that there’s no need to put baking soda in the tank, there’s nothing wrong with the rainwater,” Uncle Tilo said.
Since Hawaii Island is home to some of the most active volcanoes on Earth, with Kilauea erupting as of this writing and Mauna Loa undergoing a brief eruption in 2022, the rainwater tends to be more acidic as it absorbs sulfur and carbon oxides on its way down. Acid rain, over time, is corrosive, causing all sorts of problems with plumbing, unwanted leaching of heavy metals, and even leading to adverse effects when it comes to dental hygiene, bone density, and gastrointestinal health.
“One of them was even telling people they can’t put bleach in their catchment tanks because bleach will burn the liners,” he said. “[Macomber] was a little short on the dosage and the magic formulas, but [her guide] is what we’ve been following since we started over seven years ago.”
As bleach and baking soda are both alkaline, adding these compounds to harvested rainwater in the right amounts will reduce its acidity, preventing plumbing corrosion and greatly reducing the risk of heavy metal contamination. The added benefit of bleach also keeps algae growth and pathogens at bay, before filtration does the rest.
Despite the conceptual simplicity of harvesting rainwater from rooftops, some neglected systems in disrepair require significant and expensive upgrades, which limits the ability for users of water catchment systems to drink the water they catch. If the repairs are too costly for a rusted-out tank, clogged or corroded water lines, or a faulty water pump, Hawaii residents are left with few alternatives. Hawaii County, which is coterminous with the Big Island, does provide free water to its residents at spigots scattered throughout its districts. But the catch is that residents have to haul it themselves, and the water is only going to be as good as the containers they put it in.
With so many secondhand containers floating around for hauling water or putting up makeshift catchment systems, clean water flowing into them may get tainted with trace amounts of gasoline, diesel fuel, and other industrial chemicals not safe for human consumption, as whatever was once stored in them gets embedded into the plastic.
“A chemical company gets them in Oahu, when they’re done with them they ship them over here to [the Big Island], bubba Joe goes and buys a dozen of those 250-gallon cubes and sells them to… ‘Hey I got the alternative, you can connect six or eight of these 250-gallon cubes.’ ‘But what’s in them before you got them?’ ‘Oh they cleaned it out don’t worry about it,’” Archer said.
A Burgeoning Catchment Alternative
An alternative to hauling county water takes advantage of the high relative humidity found throughout most of Hawaii by extracting clean water directly from the air, but this technology is not without its unique challenges, either.
Chrissie Phelps is a sales representative on the Big Island for Waiea Water, a company that provides air-to-water generators and the Hydraloop gray water recycling system. As of December 2024, only four air-to-water units have been sold in Hawaii County, but this technology has the potential to be a game-changer, especially when hauling county water from the free spigots can be logistically challenging or if upgrades to home catchment systems are too cost-prohibitive in the short run.
“There’s no drinkable standard for catchment,” Phelps said. “No EPA, no state, no county. That’s the beauty of these, you’re not filtering water, you’re distilling it. I just sold one of these to an elderly couple with grandkids, this one comes with a 5-gallon tank and everyone is able to fill up a water bottle every morning.”
The Skywell 5 water-from-air machines, for which Waiea Water has exclusive distribution rights in the Pacific region, uses similar technology found in a typical dehumidifier, filtering dust and particulates out of the air and then condensing the moisture that passes over a cold coil. Under the right conditions and relative humidity, these machines can produce up to nearly 8 gallons of water per day, an amount sufficient enough for typical household drinking water requirements. While these small units don’t solve the issue of water insufficiency for other household uses like showering or laundering clothes, Waiea does sell machines much larger for commercial applications as well. But the Skywell 5 isn’t cheap, retailing as of April 2025 for $3,990. Their smallest model, the WR-2, is priced much lower at $1,990, generating approximately 2.5 gallons of water per day.
Even with price tags well above what most people would consider a bargain, a few thousand dollars is generally less than what it would cost for an entire water catchment system upgrade, once you add up all the roofing materials, an adequate filtration system, and the most costly expense of them all, the water catchment tank itself. Depending on the size of the tank, one made of galvanized steel can be priced well upwards of $10,000, and this is expected to go up even more as new tariffs imposed by the Trump administration go into effect.
“When I moved my tank, I hadn’t put a new filter system on it yet,” Phelps said. “Right now I have no filter going on, it smells a little musty but I’m not drinking it. I’m not too concerned about it, but I wouldn’t recommend someone else doing that.”
When costly maintenance projects have to be deferred, these water-from-air machines can fill the gaps and alleviate the burdensome task of hauling water from county spigots. The major hurdles, of course, are informing the community that these machines actually exist, and getting a warmer reception from the government.
Waiea Water CEO Anton Smith has been pushing various county and state agencies to embrace this technology and take advantage of federal grants that could offset the cost of these machines in areas where they’re needed most. Some, like Mayor Richard Bissen of Maui County, have been very receptive to water-from-air technology. Others are more guarded, including the Honolulu Board of Water Supply.
“It’s so simple that it’s hard,” Smith said, referring to various officials’ inability to grasp how the technology actually works, and how it could be implemented in more residential and commercial settings. “‘What’s the water source?’ Nothing, it’s the air. ‘Well what water source does it hook up to?’ Nothing. I’m not selling you bottled water, I’m selling you an appliance that makes water.”
According to Smith, the hesitancy from county and state officials has less to do with concerns about the quality of the water and more to do with the inability of the state to monetize it for their own benefit.
“There’s no permitting, therefore no one gets paid,” Smith said. “When solar came around, they fought it as well. They figure out a way to monetize it. It ends up being about money more so than about helping people.”
However, given the ongoing Red Hill water crisis and the subsequent awareness of groundwater contamination issues that followed, that sort of regulatory reluctance may be waning. “The Navy is now looking at buying machines for the Pearl Harbor residents,” he said.
Even the Hawaii Department of Health-Safe Drinking Water Branch, according to Smith, eventually gave Waiea Water a letter of approval to use their machines in various projects throughout the state, so long as Waiea made it clear that the machines are neither monitored by the Board of Water Supply nor endorsed by the state itself.
Smith was more than happy to agree to these caveats. “We don’t care if someone else starts doing [what we do] somewhere else,” he said. “It’s about helping everyone get to this stuff.”
More Than A Monetary Concern
One would be hard pressed to find anyone dismissing the idea of never having to pay a water bill ever again, but measuring water in terms of what you can’t see is more important than measuring it in dollars.
Waterborne illnesses such as E. coli, leptospirosis, and salmonella are potentially serious in their own right, but they can be treated with antibiotics. This is not the case for angiostrongyliasis, a parasitic infection more commonly known as rat lungworm disease (RLW).
The parasite made its way to Hawaii through the invasive semislug species Parmarion martensi native to Southeast Asia. While no semislugs have been found on the US mainland, the parasite that causes RLW has been documented in Florida.
The most common route of transmission is through ingesting unwashed locally grown produce contaminated with semislugs or their secretions. Another possible route is through drinking contaminated water.
While there are no known documented rat lungworm cases directly tied to drinking contaminated catchment water, the possibility is not one to brush off. RLW parasites can live in water for up to several weeks and are so small that they can even pass through certain water filters marketed to block waterborne pathogens. Under laboratory conditions, according to a peer-reviewed study, the only type of filter known to block RLW parasites is a 5-micron carbon-block filter, hence the integration of it into Uncle Tilo’s whole-house filtration system. As snails and semislugs can easily climb up almost any surface, keeping them out of a water catchment tank is almost as important as blocking their parasites from entering a home’s plumbing if they inevitably do get in somehow.
Jack Russell Brauher and his brother Mike bought six acres of land in Hawaiian Acres for $10,000 in 1979, and has been a full-time resident of the Big Island since 1983, taking up several career paths, often concurrently, as an organic farmer, firefighter, security professional, commercial fisherman, and serving as president of the Hawaiian Acres Community Association starting in 1991, ultimately leaving community politics in 2006.
Brauher noticed his first symptom of rat lungworm on New Year’s Eve 2016 while visiting Phoenix. “I noticed a metallic taste to whatever I put in my mouth,” he said.
By mid February 2017, Brauher was in the hospital for nearly a month, two weeks of which were spent in a semi-comatose state, and didn’t know he had contracted the illness until his condition became more stable.
“To this day, I still have [jaw paralysis] and pain,” Brauher said. “I had to relearn how to swallow, how to walk. It was bad. One of the biggest traumas of it is laying in a hospital bed with the TV on, and you can’t change the channel.”
That same year, doctors confirmed a blood clot in his left ankle. “This left leg nerve pain continues to dog me, and is probably the biggest detriment to my quality of life.”
Brauher suspects that he most likely contracted the disease sometime in November or December 2016 from improperly prepared produce at one of two restaurants on the Big Island. “One in particular had a very bad salad taste,” he said. “The other restaurant, is where my dining partner claimed to have had a mystery illness for weeks afterwards.”
Rat lungworm symptoms vary, ranging from mild fever and gastrointestinal disturbances all the way up to meningitis, paralysis, neurological dysfunction, and death in extreme cases. Treatment normally involves a combination of anti-parasitic drugs, steroids to reduce inflammation as the parasites die off in the body, and pain medication. As there are no vaccines for RLW, prevention is of utmost importance.
After his harrowing ordeal, Brauher doesn’t take any chances with his water quality. “I have a pre-screen [filter], a 20 [micron] right at my pump, a 10 [micron] and a 1 [micron] and then the UV filter,” he said. “I still drink water through the Berkey,” he continued, referencing a popular point-of-use countertop water filter, even with a rigorous filtration system and a sealed 10,000-gallon concrete catchment tank to prevent any possibility of infected slugs making their way in. “I don’t mind being as vigilant as I can.”
Tackling Water Insufficiency Through Increased Awareness
Short of any state and county regulations that neither the government nor Hawaii residents seem to be interested in implementing, getting potable water into people’s homes is for now best achieved at the community level, through information and education.
Renee Dang, author of Harvesting Rainwater For Your Homestead In 9 Days Or Less, has traveled extensively throughout the world, including Hawaii, to get a better grasp on the collective knowledge that has steered the direction of where water catchment and water purification are headed.
Without any regulations to guarantee potable catchment water, end users have to take it upon themselves to set up systems that will ensure their own health and safety.
“Some states would rather not have to deal with that issue, the public health issue,” Dang said. “You’re responsible all of a sudden for something so critical to your health, your family’s health, that education is really important.”
Dang plans to publish another book on rainwater harvesting this year, expanding on many of the same principles found in her first, with a greater focus on testing and cleanliness. “The first part of the book is all about figuring out what is wrong with your water,” she said. “Section two is all about keeping your water clean, and doing it inexpensively. Even things like a tank cover can go a long way.”
NSF International, a not-for-profit public health organization that tests and certifies all sorts of consumer products such as dietary supplements, food processing equipment, and water filters, does provide a standard protocol for rainwater catchment system components known as NSF P151. Its related NSF/ANSI 61 protocol covers all drinking water systems. The American Rainwater Catchment Systems Association (ARCSA) also provides certifications and educational materials for both rainwater harvesting professionals and the general public. Literature from both organizations can be very useful in getting catchment users up to speed in terms of information on water quality and minimizing the possibility of unwanted contaminants.
F’tahn Bey owns and operates WaterWise Enterprise in East Hawaii. His company specializes in catchment tank cleanings, system upgrades, installations, repairs, and monthly maintenance services, among others. After four years in the rainwater harvesting industry, Bey is all too familiar with catchment systems in need of significant modifications.
“The gutters might not be working, fungus in the pipes, mosquitoes, green water, plants growing out of the system,” Bey said.
Household water catchment setups unsuitable for potable use are often born not out of any reluctance or stubbornness, but simply because end users may not know exactly how to set them up in a way that delivers safe drinking water. Although the Hawaii Safe Drinking Water Branch does issue guidance on how to make rainwater safe for domestic use, the wording can be vague and doesn’t cover all aspects of what specifically can be done to ensure the health and safety of rainwater harvesters. Since the state and local governments obviously don’t have any control over the quality of rainwater, liability is a potential concern.
“Right now, it’s kind of like… filtration is filtration,” Bey said. “It’s an open industry. Everybody’s got the best filter. And so that’s why the county is like ‘I’m not touching it.’”
In Hawaii, regulation of rainwater is a very hard sell, but Bey floated a potential solution that one day might work as a compromise that wouldn’t be too intrusive or overbearing.
“If I moved here, and I’m off grid, I wouldn’t want anybody in my water system,” he said. “But, if I’m renting an Airbnb, and it’s commercial use, there should be regulation on water. You should have a standard and you should have an expert come out and assess your system, if it’s commercial, if it’s for business purposes, because [then it becomes a public] safety issue.”
Keeping private residential systems off-limits from regulatory oversight while implementing minimum standards for businesses reliant on catchment water could alleviate some of the problems related to water insufficiency and increase public knowledge about how these systems should be built and maintained. But getting everyone in the rainwater harvesting community and agencies tasked with overseeing such a proposal to come to a consensus on what that would look like isn’t without its challenges.
“It’s a small vocal demographic,” Bey said. “And [that can be] a rough issue to deal with.”