Naval Base Guam is a consolidated Navy installation spread across several locations on Guam. The installation supports more than 30 tenant commands, is home to Commander, Submarine Squadron Fifteen and Coast Guard Sector Guam, and serves as the home base of five Los Angeles-class submarines. The figures below describe the base’s physical setting, military history, resident community, and the U.S. Navy water system during 2024.
Contents
- Installation and geographic statistics
- Guam’s historical timeline
- World War II transformation
- Military and family community
- 2024 Navy water system
- Water-quality measurements and limits
Installation and geographic statistics
The NBG Installations page describes Naval Base Guam as a consolidated Navy installation with several components across the island. Its operational footprint is connected to Guam’s compact geography and to several specialized sites.
- Naval Base Guam supports more than 30 tenant commands.
- Commander, Submarine Squadron Fifteen is based at the installation.
- Coast Guard Sector Guam is also based there.
- Five Los Angeles-class submarines use Naval Base Guam as their home base.
- The Naval Base Guam Ordnance Annex is approximately 1 mile southeast of the main base.
- The Ordnance Annex encompasses nearly 18,000 acres.
- Polaris Point is approximately 2 miles north of the main-base front gate.
The NBG About page describes Guam as approximately 30 miles long and about 12 miles wide at its widest point. Those dimensions provide useful context for understanding how distinct installation components can be located across a relatively small island.
The same page places Naval Base Guam approximately 3,300 miles west of Hawaii and approximately 1,500 miles east of the Philippines. These are approximate distances, so they should be read as geographic descriptions rather than precise route measurements.
| Geographic or installation measure | Reported figure |
|---|---|
| Guam’s approximate length | 30 miles |
| Guam’s maximum approximate width | 12 miles |
| Naval Base Guam west of Hawaii | 3,300 miles |
| Naval Base Guam east of the Philippines | 1,500 miles |
| Ordnance Annex from main base | 1 mile southeast |
| Polaris Point from main gate | 2 miles north |
| Ordnance Annex area | Nearly 18,000 acres |
These figures come from the NBG About page and NBG Installations page. They identify the scale and relative position of the installation’s named locations without establishing a single boundary for every component.
Guam’s historical timeline
The NBG History page places the island’s Chamorro presence in a very long historical context. Archaeologists estimate that Chamorro presence on Guam extends between 1,500 and 3,000 years. The page records the first known western contact on March 6, 1521.
Several later dates mark the island’s Spanish period:
- Guam was officially claimed for the Spanish Crown in 1565.
- Jesuit missionaries arrived in 1668.
- Spanish galleons used Guam as a regular port of call for the next 250 years.
- The NBG History page describes 333 years of Spanish rule before the U.S. era.
- Guam was ceded to the United States after the Spanish-American War of 1898.
- The United States purchased Guam and other Spanish-held territories for $20 million in 1899.
The timeline includes both dates and durations. The 1565 claim, the 1668 missionary arrival, and the 1899 purchase are point-in-time historical markers. The 250-year port-of-call period and 333-year Spanish-rule figure describe longer periods presented by the NBG History page.
Guam then entered a sharply different period during World War II. The island fell to invading Japanese forces in 1941, and the Japanese occupation lasted 31 months. American forces landed on Guam on July 21, 1944.
The NBG History page reports severe human costs for the 1944 fighting. It records 1,600 American servicemen claimed by the fighting, almost the entire 18,000-member Japanese Army on the island killed, and approximately 800 Chamorro lives lost. The Japanese Army figure is described as “almost the entire” 18,000, while the Chamorro figure is explicitly approximate.
World War II transformation
After the fighting, Navy Seabees transformed jungle and mangrove swamp into a self-contained base housing 50,000 personnel. The scale of that wartime construction is reflected in the facilities listed by the NBG History page.
The World War II-era base included an expanded harbor, a repaired and expanded airfield, new docks, a ship repair facility, and a submarine base. It also included 3,000 Quonset huts and more than 1,000 major structures.
The local population was estimated at 20,000 during the World War II buildup period. That estimate is useful context for the size of the wartime base: the reported capacity of 50,000 personnel was substantially larger than the island’s estimated local population at that point in the buildup.
The wartime statistics describe construction and capacity rather than a modern inventory. The 3,000 Quonset huts, more than 1,000 major structures, and 50,000-person housing figure belong to the historical base-building account on the NBG History page and should not be treated as present-day totals.
Military and family community
The NBG History page reports approximately 6,300 active-duty Navy members living on Guam and approximately 6,900 family members living on Guam. Both numbers are approximate and are presented as community figures, not as a full count of every person supported by the installation.
| Community group | Reported population |
|---|---|
| Active-duty Navy members living on Guam | Approximately 6,300 |
| Family members living on Guam | Approximately 6,900 |
Together, these two reported groups represent approximately 13,200 people when the figures are added, but that combined figure is a simple combination of two approximate counts and should not be interpreted as an official total population. The source does not provide a corresponding total for all tenant commands, Coast Guard personnel, civilian employees, contractors, or other residents.
The distinction matters when interpreting the installation’s role in island life. Naval Base Guam supports more than 30 tenant commands, while the community figures identify only active-duty Navy members and family members living on Guam. The two descriptions measure different parts of the base-related population and should not be substituted for one another.
2024 Navy water system
The 2024 U.S. Navy Water System Consumer Confidence Report covers January 1 through December 31, 2024. It identifies the Navy water system with PWS ID GU0000010. The primary water source was the Navy (Fena) Reservoir, supplemented by Almagosa Springs and Bona Springs.
The report includes both regulated measurements and treatment-performance information. For several substances, it lists a maximum contaminant level, or MCL, alongside the detected concentration. Other entries use an action level, maximum residual disinfectant level, treatment-technique target, or reporting range. Those categories are not interchangeable.
The following entries pair the reported limit or standard with the reported result:
- Picloram had an MCL of 500 ppb and was detected at 0.17 ppb.
- Fluoride had an MCL of 4 ppm and was detected at 0.53 ppm.
- Nitrate had an MCL of 10 ppm and was detected at 2.2 ppm.
- Selenium had an MCL of 50 ppb and was detected at 4.2 ppb.
- Gross alpha activity had an MCL of 15 pCi/L and was detected at 2.3 pCi/L.
- Five haloacetic acids had an MCL of 60 ppb and were detected at 20 ppb.
- Total trihalomethanes had an MCL of 80 ppb and were detected at 54 ppb.
- Lead had an action level of 15 ppb and a reported concentration of 0.44 ppb.
- Copper had an action level of 1.3 ppm and a reported concentration of 0.36 ppm.
Water-quality measurements and limits
Some 2024 results were reported as ranges, compliance percentages, or treatment controls rather than as one concentration. Sodium was detected in the range of 16 to 52 ppm. Chlorine had an MRDL of 4 ppm and was reported in the range of 0.01 to 3.1 ppm. Total organic carbon had a treatment-technique target greater than 1.0 and was reported at 1.2 to 2.5.
The report states that turbidity met the 95% requirement at 100% compliance. Peak turbidity on June 15, 2024 was 0.212 NTU. Total coliform was reported at 2.0% positive per month in 2024. Acrylamide was controlled to a treatment-technique limit of 0.05% and was dosed at 1 ppm.
| 2024 water-system item | Reported measurement or standard |
|---|---|
| Sodium | 16–52 ppm detected |
| Chlorine | 0.01–3.1 ppm; MRDL 4 ppm |
| Total organic carbon | 1.2–2.5; target greater than 1.0 |
| Turbidity | 100% compliance with 95% requirement |
| Peak turbidity | 0.212 NTU on June 15, 2024 |
| Total coliform | 2.0% positive per month |
| Acrylamide | 1 ppm dose; 0.05% treatment-technique limit |
The report also addresses per- and polyfluoroalkyl substances. In November 2024, samples were collected from the entry points of the U.S. Navy Water System. Ten of the 25 PFAS compounds covered by the method were detected.
PFHxS had a method reporting limit of 0.3 ppt and was detected at 3.1 ppt at Well NCS 10. The report lists the EPA PFAS rule values as 4.0 ppt for PFOS, 4.0 ppt for PFOA, 10 ppt for GenX, 10 ppt for PFNA, and 10 ppt for PFHxS. It also lists a PFAS hazard index MCL of 1.0 unitless.
These PFAS figures identify the sampling period, location, analytical reporting limit, detected concentration, and listed rule values. They should be read within the 2024 U.S. Navy Water System Consumer Confidence Report rather than generalized to every water source on Guam or to later years.