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2025 Groundwater Status Reports
November 2025 Groundwater Levels Status Report | December 2025 Groundwater Levels Status Report
Nine aquifer index stations remained in low groundwater condition for the production months of November and December 2025. Beretania, Kalihi, Moanalua, Pearl City, Waipahu, Kaluanui and Waialua are in Caution Status. Kaimuki and Punalu'u are in Alert Status. The monthly production average decreased between November and December 2025, from 137.31 to 129.81 million gallons per day.
The Board of Water Supply rainfall index increased between November and December 2025, from 92 to 131 percent of normal, with a 5-month moving average of 58 and 66 percent, respectively. Between the publication dates of December 2, 2025 and January 6, 2026, the Hawai'i Drought Monitor shows a reduction in drought conditions; as of January 6, 2026, there were no drought conditions across the interior of O'ahu, with abnormally dry conditions along much of the coast, grading to moderate drought along the southeastern coast. Between December 2025 and January 2026, the National Weather Service scaled back its forecast of above-normal precipitation from May to April 2026.
Most monitoring wells exhibited relatively stable head levels through the months of November and December 2025. This likely reflects the relatively higher rainfall over the past two months, combined with seasonal decreased production. While average monthly production for November 2025 was slightly higher than November 2024 and just above the 5-year monthly average, average monthly production for December 2025 was significantly lower than December 2024 (a period extremely low rainfall) and almost identical to the 5-year monthly average.
October 2025 Groundwater Levels Status Report
Nine aquifer index stations were in low groundwater condition for the production month of October 2025. Beretania, Kalihi, Moanalua, Pearl City, Waipahu, Kaluanui, and Waialua are in Caution Status. Kaimukī and Punalu'u are in Alert Status. The monthly production average for October 2025 was 145.51 million gallons per day.
The Board of Water Supply rainfall index for the month of October 2025 was 53 percent of normal, with a 5-month moving average of 55 percent. As of November 11, 2025, the Hawai'i Drought Monitor shows abnormally dry conditions across most of O'ahu, grading to moderate drought conditions along all but portions of the northern and windward coasts, then to severe drought conditions along a small portion of the southeastern coast. The National Weather Service is forecasting above-normal precipitation beginning in November 2025, through March 2026.
Most monitoring wells exhibited slightly decreasing head levels for the month of October 2025. This likely reflects the lower rainfall over the past several months, combined with seasonal increased production. Average monthly production for October 2025 is slightly higher than October 2024 and the 5-year monthly average.
September 2025 Groundwater Levels Status Report
Nine aquifer index stations were in low groundwater condition for the production month of September 2025. Beretania, Kalihi, Moanalua, Pearl City, Waipahu, Kaluanui, and Waialua are in Caution Status. Punalu'u is in Alert Status. KaimukT is in Critical Status. The monthly production average for September 2025 was 153.02 million gallons per day.
The Board of Water Supply rainfall index for the month of September 2025 was 36 percent of normal, with a 5-month moving average of 70 percent. As of October 7, 2025, the Hawai'i Drought Monitor shows abnormally dry conditions across most of O'ahu, grading to moderate drought conditions along all but portions of the northern and windward coasts, then to severe drought conditions along a small portion of the southeastern coast. The National Weather Service is forecasting above-normal precipitation beginning in November 2025, through February 2026.
Most monitoring wells exhibited decreasing head levels for the month of September 2025. This likely reflects the lower rainfall over the past several months, combined with increased production. Average monthly production for September 2025 is notably higher than September 2024 and the 5-year monthly average.
August 2025 Groundwater Levels Status Report
Six aquifer index stations were in low groundwater condition for the production month of August 2025. Pearl City, Waipahu, Kaluanui, and Waialua are in Caution Status. Punalu'u is in Alert Status. Kaimuki is in Critical Status. The monthly production average for August 2025 was 153.14 million gallons per day.
The Board of Water Supply rainfall index for the month of August 2025 was 18 percent of normal, with a 5-month moving average of 89 percent. As of September 9, 2025, the Hawai'i Drought Monitor shows abnormally dry conditions across most of O'ahu, grading to moderate drought conditions along the entire leeward coast, then to severe drought conditions along a small portion of the southeastern coast. The National Weather Service is forecasting above-normal precipitation beginning in October 2025, through February 2026.
Most monitoring wells exhibited decreasing head levels for the month of August 2025. This likely reflects the lower rainfall over the past several months, combined with seasonally increasing production. Average monthly production for August 2025 is higher than August 2024 and the 5-year monthly average.
July 2025 Groundwater Levels Status Report
Five aquifer index stations were in low groundwater condition for the production month of July 2025. Pearl City, Waipahu, and Waialua are in Caution Status. Kaimuki and Punalu'u are in Alert Status. The monthly production average for July 2025 was 147.32 million gallons per day.
The Board of Water Supply rainfall index for the month of July 2025 was 90 percent of normal, with a 5-month moving average of 94 percent. As of August 5, 2025, the Hawai'i Drought Monitor shows abnormally dry conditions primarily across the central, northwest, and southeast portions of O'ahu, grading to moderate drought conditions along the leeward coast. The National Weather Service is forecasting below-normal precipitation through at least September 2025.
Most monitoring wells exhibited decreasing head levels for the month of July 2025. This likely reflects the relatively lower rainfall over the past two months, combined with seasonally increasing production. Average monthly production for July 2025 is slightly higher than July 2024 and the 5-year monthly average.
June 2025 Groundwater Levels Status Report
Four aquifer index stations were in low groundwater condition for the production month of June 2025. Pearl City and Waialua are in Caution Status. Kaimuki and Punalu'u are in Alert Status. The monthly production average for June 2025 was 143.96 million gallons per day.
The Board of Water Supply rainfall index for the month of June 2025 was 77 percent of normal, with a 5-month moving average of 82 percent. As of July 8, 2025, the Hawai'i Drought Monitor shows abnormally dry conditions across O'ahu, grading to moderate drought conditions along the leeward coast. The National Weather Service is forecasting below-normal precipitation through at least September 2025.
Most monitoring wells exhibited stable to slightly decreasing head levels for the month of June 2025. This likely reflects the relatively lower rainfall combined with seasonally increasing production. Average monthly production for June 2025 is higher than June 2024 and the 5-year monthly average.
May 2025 Groundwater Levels Status Report
Four aquifer index stations were in low groundwater condition for the production month of May 2025. Pearl City and Waialua are in Caution Status. Kaimuki and Punalu'u are in Alert Status. The monthly production average for May 2025 was 136.70 million gallons per day.
The Board of Water Supply rainfall index for the month of May 2025 was 127 percent of normal, with a 5-month moving average of 104 percent. As of June 10, 2025, the Hawai'i Drought Monitor shows no drought conditions along most of the windward coast of O'ahu, grading to abnormally dry conditions over much of the leeward and eastern portions of the island, further grading to moderate drought conditions along a small portion of the leeward coast. The National Weather Service is forecasting above-normal precipitation through August 2025.
Most monitoring wells exhibited stable to slightly decreasing head levels for the month of May 2025. This likely reflects the relatively higher rainfall offset by seasonally increasing production. Average monthly production for May 2025 is higher than May 2024 and the 5-year monthly average.
April 2025 Groundwater Levels Status Report
Four aquifer index stations were in low groundwater condition for the production month of April 2025. Pearl City and Waialua are in Caution Status. Kaimuki and Punalu'u are in Alert Status. The monthly production average for April 2025 was 135.99 million gallons per day.
The Board of Water Supply rainfall index for the month of April 2025 was 131 percent of normal, with a 5-month moving average of 82 percent. As of May 6, 2025, the Hawai'i Drought Monitor shows no drought conditions along most of the windward coast of O'ahu, grading to abnormally dry conditions over most of the island, further grading to moderate drought conditions along the leeward coast. The National Weather Service is forecasting above-normal precipitation through August 2025.
Most monitoring wells exhibited stable to slightly decreasing head levels for the month of April 2025. This likely reflects the prior two months of significantly lower-than-average rainfall, coupled with seasonally increasing production.
Average monthly production for April 2025 is slightly higher than April 2024 and the 5-year monthly average.
March 2025 Groundwater Levels Status Report
Three aquifer index stations were in low groundwater condition for the production month of March 2025. Waialua is in Caution Status. Kaimuki and Punalu'u are in Alert Status. The monthly production average for March 2025 was 132.65 million gallons per day.
The Board of Water Supply rainfall index for the month of March 2025 was 44 percent of normal, with a 5-month moving average of 72 percent. As of April 1, 2025, the Hawai'i Drought Monitor shows drought conditions across the entire island of O'ahu, with abnormally dry conditions over most of the island, grading to moderate drought conditions along the leeward coast and far eastern end of the island. The National Weather Service is forecasting above-normal precipitation through June 2025.
Most monitoring wells exhibited slightly decreasing head levels for the month of March 2025. This likely reflects the past two months of significantly lower-than-average rainfall.
The National Weather Service Precipitation Summary for March 2025 notes that "March is normally one of the wettest months of the year, especially for the windward slopes of the state. It was not a normal March in 2025... Most of the (NOAA) rain gauges on O'ahu had near to below average rainfall totals... Two consecutive dry months have offset the wet conditions of late January.
Average monthly production for March 2025 is slightly higher than March 2024 and the 5-year monthly average.
February 2025 Groundwater Levels Status Report
Three aquifer index stations were in low groundwater condition for the production month of February 2025. Punalu'u and Waialua are in Caution Status. Kaimuki is in Alert Status. The monthly production average for February 2025 was 129.26 million gallons per day.
The Board of Water Supply rainfall index for the month of February 2025 was 29 percent of normal, with a 5-month moving average of 87 percent. As of March 4, 2025, the Hawai'i Drought Monitor shows moderate drought conditions across the entire island of O'ahu. The National Weather Service is forecasting above-normal precipitation through May 2025.
Most monitoring wells exhibited stable to slightly increasing head levels for the month of February 2025. This likely reflects the combined effects of low winter production and the previous month's significantly higher-than-average rainfall. Average monthly production for February 2025 is slightly higher than February 2024 and the 5-year monthly average.
January 2025 Groundwater Levels Status Report
Three aquifer index stations were in low groundwater condition for the production month of January 2025. Waialua is in Caution Status. Kaimuki and Punalu'u are in Alert Status. The monthly production average for January 2025 was 132.85 million gallons per day.
The Board of Water Supply rainfall index for the month of January 2025 was 190 percent of normal, with a 5-month moving average of 89 percent. As of February 4, 2025, the Hawai'i Drought Monitor shows abnormally dry to moderate drought conditions along the southern coast of O'ahu. The National Weather Service is forecasting above-normal precipitation through May 2025.
Most monitoring wells exhibited stable head levels for the month of January 2025. This likely reflects the combined effects of slightly higher-than-average production (but lower than summer maximums) and increased rainfall following two months of low rainfall.
Average monthly production for January 2025 is higher than January 2024 and higher than the 5-year monthly average.
Updated: 12/08/2025