| The Water Systems In Maui County | Where Does Your Water Come From? | Monthly Water Production |
| Maui's Water Treatment Facilities (WTF) | Water Quality Reports | Water Conservation |
THE WATER SYSTEMS IN MAUI COUNTY
The Maui Department of Water Supply serves five main sections within the County: Central Maui, Upcountry Maui, West Maui, East Maui, and Molokai. The system with the most customers is the Central system, which includes Wailuku, Paia, Kahului, and Kihei. The next largest system is the Upcountry water system, which is actually the largest geographically. This includes Kula, Pukalani, Makawao, and Haiku. Lahaina is third, then Molokai, and then Hana. Water on the island of Lanai is provided by a private company.
WHERE DOES YOUR WATER COME FROM?
As the sun shines on the Pacific Ocean, water evaporates into clouds, and the tradewinds from the northeast bring the clouds to the islands. The rain forest in the mountains "catch" the clouds and the cool mountain air condenses the clouds to form rain. In some areas up to 300 inches of rain falls each year! The rain does many things -- it feeds plants, evaporates, and also flows back into the ocean.Some of the rain flows into streams and ditches, and some percolates down to underground aquifers (huge water volumes formed by the fresh water floating on salt water and moving in volcanic rock voids). The aquifers provide most of the water for Central Maui, East Maui, Molokai, and parts of Lahaina.
Groundwater, or water from the underground aquifers, is naturally filtered by lava rocks. It's about as pure as it gets. The Department of Water Supply pumps the water up to the surface, treats it to provide disinfection, and delivers it to your tap.
In a few areas there are pesticide residuals in untreated water. The Department of Water Supply uses a simple technology that's similar to what people use to treat their aquariums. It's called Granular Activated Carbon (GAC) and it removes the pesticide residuals to nondetectable levels, making the water safe to drink. The DWS has GAC facilities at Napili Well 'A' and at the Hamakuapoko Wells (which are not in use).
Upcountry relies on water from East Maui's streams and ditches. Parts of Lahaina also get water from the streams and ditches that flow from the West Maui Mountains. This water is called surface water. Surface water must be filtered first so we have three treatment plants Upcountry, two in Lahaina, and one in Wailuku. Sometimes there are bacteria in the water like giardia and liptospirosis but the treatment plants take all that out so the water is safe to drink. The water is also disinfected and then distributed to our customers.
All of our treatment and disinfection processes follow the federal government's Environmental Protection Agency (EPA) rules. The Hawaii State Department of Health enforces these rules.
Graphical Representation of the Water Cycle
(schematic courtesy of Honolulu Board of Water Supply)
Groundwater pumped from underground aquifers is the main source of water for Central Maui, East Maui, Molokai, and supplements the Lahaina and Upcountry water systems. Treated surface water is the primary source of water for Upcountry and Lahaina. Monthly pumping and treatment data is available in the chart below. Numbers below are daily averages in thousands of gallons.
AREA 04/07 05/07 06/07 07/07 08/07 09/07 10/07 11/07 12/07 01/08 02/08 03/08 Prev. 12 months Central Maui Groundwater-Iao 18,327 18,556 19,107 19,922 18,804 16,856 15,290 13,715 11,829 13,142 13,215 15,306 16,180 Groundwater-Waihee 4,003 5,100 5,201 4,468 5,662 6,591 6,413 6,188 5,466 5,877 5,783 5,563 5,525 Kepaniwai 813 813 812 813 755 740 740 728 732 742 742 735 764 Iao Tunnel 1,737 1,717 1,686 1,688 1,351 1,199 1,263 1,256 1,343 1,268 1,226 1,269 1,417 Surface Water 691 1,222 1,573 1,444 1,388 1,370 1,730 1,680 728 1,121 1,073 1,515 1,295 Total 25,571 27,407 28,380 28,335 27,961 26,757 25,437 23,567 20,099 22,149 22,037 24,388 25,181 Upcountry Maui Surface Water 7,478 8,666 8,551 7,878 7,173 6,827 7,258 6,124 4,479 4,847 4,547 6,357 6,688 Groundwater 481 817 1,704 622 748 476 350 539 999 993 1,084 1,271 840 Total 7,959 9,483 10,255 8,501 7,921 7,302 7,608 6,663 5,478 5,840 5,630 7,629 7,527 West Maui Surface Water 3,286 3,220 3,159 3,465 3,424 3,341 3,491 3,327 2,795 3,270 2,935 3,187 3,243 Groundwater 2,639 3,005 3,306 3,302 3,287 3,090 2,715 2,392 2,577 2,441 2,449 2,689 2,826 Total 5,925 6,225 6,465 6,768 6,710 6,430 6,206 5,719 5,372 5,711 5,383 5,875 6,069 East Maui Groundwater 294 321 336 334 300 290 299 283 303 303 300 355 310 Molokai Groundwater 1,259 1,427 1,513 1,497 1,412 1,370 1,324 1,107 959 1,067 1,083 1,301 1,277 TOTAL WATER PRODUCTION 41,007 44,863 46,949 45,435 44,305 42,149 40,873 37,339 32,211 35,070 34,435 39,548 40,364
MAUI'S WATER TREATMENT FACILITIES (WTF)
(For more information about the facilities, see the table on the water quality report page.)
KAMOLE WEIR:
Water Source:
Wailoa DitchService Area:
Pukalani, Makawao,
Haliimaile, HaikuDesign by: M & E Pacific
Construction by: Construction Development, Inc.The largest surface water treatment facility on Maui is the Kamole Weir WTF in Haliimaile. It is located approximately 1,120 feet above sea level and relies on flow from the Wailoa Ditch. Originally built in the early 1970s, Kamole was upgraded to Memcor microfiltration, which was put into service in June 1998. Treated water from the facility goes to 6,571 services and can supply water to almost the entire region (9,708 services) if necessary. The facility has four booster pumps to move water up to the 2,800-foot elevation, where it can be pumped to the highest service areas at 4,500 feet (Haleakala Acres). The Kamole WTF is the primary source of water for nearly all of Upcountry during times of drought. This facility won the American Public Works Association Hawaii Chapter 1999 Project of the Year in the environmental $2 - $10 million category. Kamole is currently the third largest microfiltration facility for surface water in the USA (the two largest are in Wisconsin). Kamole's average daily production is 3.6 million gallons per day (MGD).
PIIHOLO:
Water Source:
Waikamoi
ForestService Area:
Lower KulaDesign by: ECM and Brown & Caldwell
Construction by: Fletcher PacificTo meet regulatory requirements and address the Lower Kula water quality problem, the Piiholo WTF was built in 1996. The site access road improvements and treatment plant required 3 years to build at a construction cost of $15.7 million. The facility is located in the Makawao Forest Reserve adjacent to the 50 MG Piiholo Reservoir. Piiholo uses direct filtration to treat its water and uses chlorine as a disinfectant. Piiholo's average daily production is 2.5 MGD.
OLINDA (UPPER KULA):
Water Source:
Waikamoi
ForestService Area:
Upper Kula, Ulupalakua,
KanaioDesign by: M & E Pacific
Construction by: Kiewit PacificThe original Olinda WTF was built in 1988, and to comply with the EPA's Safe Drinking Water Act, the upgrade to microfiltration was completed in June 1998. After treatment, disinfection is provided by a small amount of anhydrous ammonia, which is blended with chlorine to form chloramines (see the chloramines page for more information). The water that supplies the Olinda WTF comes from the Waikamoi Rain Forest, and is stored in the 30 MG Waikamoi Reservoirs and 100 MG Kahakapao Reservoirs. These reservoirs will also supply the non-potable agricultural line currently under construction. This is a joint project with the State Department of Agriculture, the Natural Resources Conservation Service, and the Maui DWS. The ag line will provide untreated surface water to farmers in Upper Kula. This facility's average daily production is 1.6 MGD.
LAHAINA:
Water Source:
Kanaha
StreamService Area:
LahainaWTF and Tank Design by: Austin Tsutsumi & Associates
WTF Construction by: Bodell Wheelwright Construction
Tank Construction by: Goodfellow BrothersThe Lahaina WTF is located above Lahainaluna High School, adjacent to a 1 MG water storage tank which was completed in December 1995. The Lahaina WTF was completed in June 1997 at a cost of about $10 million. This project was paid for in part with State DOE funds in exchange for 100,000 gallons of water per day at no charge for Lahainaluna High School. This facility utilizes microfiltration to treat surface water and chlorine to disinfect it after treatment. The facility's source of water is the Kanaha Stream and its average daily production is 1.6 MGD.
MAHINAHINA:
Water Source:
Honokohau
DitchService Area:
Lahaina, Napili, Wahikuli,
Kahana, AlaeloaDesign by: Austin Tsutsumi & Associates and Camp Dresser & McKee
Construction by: Bodell Wheelwright ConstructionThe Mahinahina WTF is located near the Kapalua airport and draws from three primary sources of raw surface water. The two major sources are the Honokohau and the Honolua Streams. The other water source is the Kanaha Stream. Mahinahina utilizes pre-sedimentation to treat raw surface water. Rapid mix, flocculation, and direct filtration with a mixed media filter are used. After this process, chlorine is added for disinfection. The approximate cost of the construction of this facility was $18 million. Mahinahina's average daily production is 2.4 MGD.
The Water Quality Reports describe where your water comes from, anything that may have been detected in the water, and how those results compare to standards for safe drinking water. It shows that your water is safe to drink and complies with federal and state standards.Please go to the water quality report page to see the current water quality test results for all of Maui County's water systems.
If you have any questions about the quality of your water, there are several places you may call:
The EPA hotline is 1-800-426-4791.
The Hawaii State Department of Health, Safe Drinking Water Branch phone number is 984-2400, extension 64258 (Toll free number from Molokai and Lanai: 1-800-468-4644, ext. 64258).
The Department of Water Supply Laboratory number is 270-7550.
The hydrologic cycle goes on and on. After you use water, it eventually returns to the ocean through various disposal outlets. However, there is the same amount of water today as there was when the Hawaiians first settled on the islands. There's just a lot more people using the same amount. So the Department of Water Supply's job is to find more sources to satisfy that demand. That's not easy, and it's very expensive. There are many ways you can help us conserve the supply of water that we already have. Conserving water helps save you money, too.
Be sure to check out the water conservation page for much more information about this topic.
- Use low-flow plumbing fixtures
- Find and repair leaks
- Turn off water when washing your car
- Only use the dishwasher or laundry machine when it's full
- Don't flush the toilet unnecessarily
- Turn off the water while shaving or brushing your teeth
- Water the yard in the early morning or evening
- Landscape your yard with plants that are appropriate for your area's rainfall
- Attach a rain sensor to your sprinkler system
- Water the yard, not the sidewalk, the driveway, or the road
| Call the Department of Water Supply at 270-8046 if you have questions about any of the topics above or if you need additional information. We're here to serve the community of Maui! |
