Tap Truth EPA drinking water records, in plain English

Public water system record

U.S. Navy Water System

On record as serving Guam, GU · Serves 12,780 people

Federal records show 2 health-based violations and no monitoring/reporting issues for U.S. Navy Water System in the last ten years. The most serious issue in this window was a resolved Total Trihalomethanes (TTHMs) violation.

  • GU0000010
  • FP
  • AP
  • 12,780 served

System profile

Source water Surface water
ZIP 96540
EPA system ID GU0000010

Verify this system on EPA ECHO →

Health-based violations, last 10 years
2
Resolved
2
Unresolved
0
Any acute record
Yes
Monitoring issues, last 10 years
0

Key facts

  • U.S. Navy Water System draws water from 13 wells, 1 surface water intake and 2 springs.
  • Highest measured level in the last 10 years: Total Trihalomethanes (TTHMs), 0.901 mg/L, federal limit 0.08 mg/L (11 times the limit), 2023.
  • Most recent enforcement action: boil water order by Guam, May 2023.
  • Record on file since 1980, with 2 health-based violations before October 19, 2016.
  • Lead pipe inventory: 0 lead and 0 unknown out of 1,056 service lines.

Check whether U.S. Navy Water System serves your address

Address suggestions by Mapbox

Health-based violations

Since October 2016

Violation data reflects EPA records through March 2026. For the most current status, visit the EPA ECHO database.

Contaminant Rule family Start date Status Acute
Total Trihalomethanes (TTHMs)
Contaminant limit exceeded
Measured 0.901 mg/L, federal limit 0.08 mg/L (11 times the limit)
 220 Jul 1, 2023 Resolved No
Revised Total Coliform Rule
Contaminant limit exceeded
 110 May 1, 2023 Resolved Yes

Full record since 1980

EPA's records for U.S. Navy Water System go back to 1980. Before October 19, 2016 they list 2 health-based violations (2 archived by EPA without a recorded fix) and 3 monitoring or reporting violations.

Violations that began in Health-based Monitoring and reporting
1980s 0 1
2010 to October 18, 2016 2 2
2020s 2 0

Most recent health-based violation before October 19, 2016: Surface Water Treatment Rule, began September 2011, Archived.

Show all 2 health-based violations before October 19, 2016
Contaminant Start date Status
Surface Water Treatment Rule
Treatment technique failure
 Sep 1, 2011 Archived
Total Coliform (acute)
Contaminant limit exceeded
 Mar 1, 2011 Archived

Enforcement actions

Guam regulators issued 2 boil water orders to U.S. Navy Water System between 2013 and 2023. The most recent was a boil water order in May 2023.

Date By Action Violations covered
May 31, 2023 Guam Boil water order 1 violation (1 health-based): Revised Total Coliform Rule
Oct 3, 2013 Guam Boil water order 1 violation (1 health-based): Total Coliform

What the violations mean

Total Trihalomethanes (TTHMs)

1 incident

Disinfection byproduct levels exceeded the federal limit

Long-term TTHM exposure may increase bladder cancer risk

Revised Total Coliform Rule

1 incident

The system did not meet a requirement of the Revised Total Coliform Rule

Coliform and E. coli rules protect against bacteria in the distribution system

Where the water comes from

U.S. Navy Water System draws water from 13 wells, 1 surface water intake and 2 springs. It also buys water from Gwa Central Water System. It also has an emergency connection to Guam Regional Medical City. 1 other community water system buys water from U.S. Navy Water System. 1 other public water system has an emergency connection to U.S. Navy Water System.

Buys water from

Emergency or part-time connections to

  • Guam Regional Medical City Dededo, GU

Community systems that buy water from it

Annual water quality report

U.S. Navy Water System must give its customers an annual water quality report (Consumer Confidence Report) by July 1, with the levels its tests found in the previous year.

Systems serving 10,000 or more people must mail or deliver the report to every customer, and from 2027 they must send it twice a year.

Find a posted report with EPA's Consumer Confidence Report search

Testing your own water

To test the water at your tap, or a private well this record does not cover, use a laboratory certified for drinking water by Guam.

Certified drinking water labs by state EPA guidance for private wells