CTAHR Banner
UH Manoa Logo
CTAHR In Action
site map button
nav bar rule
academic & student affairs button
extension/outreach button
research button
nav bar rule
administration button
departments button
counties button
international button
nav bar rule
college activities button
alumni affairs button
k-12 & teachers button
for employees button
nav bar rule
ctahr directory button
nav bar rule
search button
horizontal rule
CTAHR helps rural residents learn to manage a precious resource: catchment water
photo of Trisha Macomber preparing to analyze a water catchment system sample for contamination
Trisha Macomber, educational specialist with the Department of Natural Resources and Environmental Management, preparing to analyze a water catchment system sample for contamination.
With as many as 60,000 people in Hawaii depending on rainwater for most—sometimes all—of their household water needs, and with many regions of the state not having known the benefits of piped-in municipal water, it’s timely that CTAHR is publishing a user’s manual on rainwater catchment systems. Various county agencies and the Hawaii Department of Health’s Safe Drinking Water Branch have provided some advice and assistance, but no one “wrote the book” on the subject until Trisha Macomber got the idea to do it.

A Big Island resident with a Master’s degree in public health, Macomber began working for CTAHR as an analytical chemist, then became an education specialist in the Department of Natural Resources and Environmental Management. When she saw an opportunity to fill a community need for information on a vital quality-of-life factor—reliable rural catchment water with minimized health risk to its users—she undertook extensive research on the subject and developed a vision and a program to extend the knowledge throughout the state.
With the publication this year of CTAHR’s Guidelines on Rainwater Catchment Systems for Hawaii, Macomber’s efforts have taken off, with the goal to reach every family that depends on stored rainwater for some of their water needs. Helping achieve this goal are the Hawaii Department of Health and the Big Island’s office of the Rural Community Assistance Corporation. The two agencies shared the cost of printing 10,000 copies, allowing free distribution of the 52-page book to the public.

 Guidelines on Rainwater Catchment Systems for Hawaii order form Rainwater Catchment Systems for Hawaii brochure
(Single copies are available free to requestors; businesses and associations can purchase bulk quantities at a low price for their clients or members—click here for the order blank.)
As most world travelers know, drinking the local water is a major health risk for those unaccustomed to the organisms that may contaminate it. Even for the people who are accustomed to a poor water supply, chronic infection from unsafe water is a major cause of poor health and disease in much of the less-developed world. While this type of risk is unknown to visitors and most residents in Hawaii, who enjoy some of the purest and cleanest municipal water available on Earth, many of our rural residents who use rainwater for some or all of their water needs are at risk from their catchment systems. Knowledge of potential hazards and risk-minimization strategies is the key, and Macomber’s book spells these out in detail, “from the raindrop to the faucet.”
photo of water catchment on Hawaii 02 photo of water catchment on Hawaii 02
Two typical types of water catchment tank in use on the island of Hawaii. At left is an example of a large swimming pool tank, which are popular for their low price and ease of assembly. At right is an older tank made of redwood, a material rarely used these days.
As she gathered information, Macomber realized that a key water test was not readily available to rural residents in Hawaii. While CTAHR’s Agricultural Diagnostic Service Center, as well as commercial laboratories, conduct analyses to reveal levels of mineral hazards such as nitrates or lead, testing for biological contaminants was not readily available. Macomber began a program to test water samples and raise awareness of this health threat. The simple presence-absence test so far has shown that about 60 percent of the samples Big Island residents have brought to Macomber are contaminated with fecal bacteria indicators. Because this aspect of catchment water quality is so important, Macomber began working with the laboratory that manufactures the test reagents, urging them to design a home test kit. The kits are currently available at the CTAHR Cooperative Extension Service’s Hilo office during this pilot program phase. Macomber hopes that soon individuals will be purchasing the kits directly from the manufacturer and that community associations will make the kits available to their members.
photo of U-shaped downspout-to-tank configuration photo of ideal downspout configuration
The U-shaped downspout-to-tank configuration at left is typical but undesirable. The pipe runs down from the roof, across the ground, then up and over the tank. Between rains, water is left standing in the pipe. In the system at right, the downspout is completely drained by gravity.
Another way to improve water quality is to expand the technology options available to address the problems. Researching and introducing new technologies that are affordable and practical for Hawaii is another facet of Macomber’s work. Rural homeowners are encouraged to contribute to this effort by sharing their own innovations and ideas.

Trisha’s Macomber’s efforts are just one facet of CTAHR’s work with Hawaii’s water. Ensuring adequate supplies for agriculture to ensure green, open space and a viable agricultural economy is a key emphasis in these days of increasing urbanization and politicization of water-use issues. Managing livestock wastes to prevent contamination of surface water bodies and groundwater has been another major activity of CTAHR’s research. And CTAHR’s program on water quality, in concert with federal coastal zone management programs, helps raise awareness of pollution sources that threaten our water supply and our vital streams, bays, near-shore ocean, and reefs. One branch of that program, called the HAPPI program (Hawaii’s Pollution Prevention Information) offers dozens of free publications on various pollution sources that can come from our homes and farms.
photo of catchment system water samples with and without bacterial contamination
The two catchment system water samples at left indicate contamination with fecal bacteria indicators; the two at right are not contaminated.
Hawaii’s future and Hawaii’s waters are intimately and inextricably linked, and CTAHR’s scientists and extension workers are committed to protecting and preserving the islands’ essential life-sustaining resources.

For more information on water catchment systems and the fecal bacteria indicators testing, contact Trisha Macomber at the CTAHR Cooperative Extension Service Hilo office (808) 981-5199 or email macomber@hawaii.edu.
horizontal rule
Posted February 15, 2002

Search Site linkContact Us linkSite Map linkCTAHR News linkCTAHR Home link