Is Talofofo, GU Tap Water Safe to Drink?
Graded B+ — but Copper, Chromium-6 and 1 more were detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓
81.4/100
waterverge.com Talofofo, GU — Water Quality Report
Talofofo's drinking water received a grade of B+ (81.4 out of 100), indicating good water quality. The city's 2 water systems serve approximately 145,008 residents using groundwater.
Lead levels were measured at 0.9 ppb (90th percentile), well within EPA limits. UCMR 5 testing detected 11 PFAS compounds, with levels exceeding EPA maximum contaminant levels in the water supply.
The system has 27 violations on record, including 5 health-based violations. 2 remain unresolved.
What to know about Talofofo's water
Talofofo ranks #10 out of 16 cities in Guam for water quality, placing it below average in the state.
Talofofo relies on groundwater, which is generally less vulnerable to surface contamination but can be affected by naturally occurring minerals like arsenic and nitrate, as well as agricultural and industrial runoff.
Of particular concern: PFAS "forever chemical" levels exceed the 2024 EPA maximum contaminant levels. These synthetic compounds don't break down naturally and require specialized filtration such as reverse osmosis or granular activated carbon.
Hexavalent chromium (chromium-6) was detected at 26.00 µg/L, above California's 10 µg/L limit. There is no federal MCL, but the EPA is reviewing evidence linking long-term exposure to cancer risk.
Water quality score
See methodology →Is Talofofo, GU water safe to drink?
Talofofo's tap water meets most EPA standards but has areas that warrant attention. With a grade of B+ (81.4/100), some contaminant levels or compliance issues suggest that residents may benefit from additional filtration. The city's 2 water systems serve approximately 145,008 residents using groundwater (wells).
Recent water quality updates for Talofofo
A timeline of significant water quality events, violations, and data updates.
PFAS levels exceed EPA maximum contaminant levels. Reverse osmosis or activated carbon filtration recommended.
Latest EPA compliance and testing data incorporated into Talofofo's water quality assessment. Grade: B+ (81.4/100).
1 health-based. Contaminants: Revised Total Coliform Rule.
1 health-based. Contaminants: Total Haloacetic Acids (HAA5).
3 health-based. Contaminants: Mercury.
Key contaminant findings
Based on the most recent EPA sampling data for Talofofo's water supply.
Well within EPA limits.
Exceeds EPA action level. Copper can leach from household plumbing — flush taps for 30 seconds before drinking.
PFAS "forever chemicals" exceed EPA maximum contaminant levels. Reverse osmosis or granular activated carbon filtration strongly recommended.
The "Erin Brockovich" chemical. There is no federal MCL, but California has set a limit of 10 µg/L. Reverse osmosis filtration is effective at removing hexavalent chromium.
PFAS "forever chemicals" detected
UCMR 5 testing found 11 PFAS compounds in Talofofo's water supply. PFAS are synthetic chemicals that persist indefinitely in the environment and the human body.
Violation history
Talofofo's water system has 27 total violations on record, including 5 health-based violations. 2 remain unresolved.
Where does Talofofo's water come from?
Talofofo's drinking water comes from groundwater (wells), supplied by 2 water systems serving approximately 145,008 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate. Nearby water bodies include La Sa Fua River Near Umatac, Guam (river), Imong River Near Agat, Guam (river), Almagosa River Near Agat, Guam (river), Maulap River Near Agat, Guam (river), Fena Dam Spillway Near Agat, Guam (lake).
What Talofofo residents can do
Recommended: Reverse osmosis system. This addresses the specific contaminants found in Talofofo's water.
Your water utility is required to publish an annual Consumer Confidence Report (CCR) with detailed testing results. Ask for the latest copy or check your utility's website.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Forever chemicals overview
National PFAS report →Violation summary
Violations & advisories
Recommended water filters
Based on contaminants detected in Talofofo's water supply, we recommend the following filter types.
Full contaminants report
| Contaminant | Detected Level | EPA Limit | Unit | Category | Status |
|---|---|---|---|---|---|
| Lead (90th percentile) LeadHeavy Metal A toxic heavy metal that can leach into drinking water from older pipes, solder, and fixtures. No amount of lead in water is considered safe. Health EffectsBrain and nervous system damage in children, kidney damage, high blood pressure, and reproductive problems in adults. EPA Limit15 ppb action level Common SourcesCorrosion of lead pipes, lead solder, brass faucets, and household plumbing. | 0.9 | 15 | ppb | Inorganic | Safe |
| Copper (90th percentile) CopperInorganic A metal that enters drinking water mainly through corrosion of copper plumbing. Small amounts are essential for health, but excess levels are harmful. Health EffectsGastrointestinal distress (nausea, vomiting, diarrhea) at short-term high levels; liver and kidney damage from long-term exposure. EPA Limit1.3 mg/L action level Common SourcesCorrosion of copper household plumbing, erosion of natural deposits. | 53.00 | 1.3 | mg/L | Inorganic | Over Limit |
| 11Cl-PF3OUdS | ND | HI | µg/L | PFAS | Not Detected |
| 4:2 FTS | ND | HI | µg/L | PFAS | Not Detected |
| 6:2 FTS 6:2 FTSPFAS A fluorotelomer sulfonate commonly found at sites contaminated with aqueous film-forming foam (AFFF) used in firefighting. Health EffectsPotential liver toxicity and endocrine disruption. Less studied but identified as a contaminant of concern. EPA LimitNo individual MCL (not yet regulated) Common SourcesFirefighting foam (AFFF), airports, military bases, and industrial facilities. | 0.148 | HI | µg/L | PFAS | Detected |
| 8:2 FTS | 0.007 | HI | µg/L | PFAS | Detected |
| 9Cl-PF3ONS | ND | HI | µg/L | PFAS | Not Detected |
| ADONA | ND | HI | µg/L | PFAS | Not Detected |
| HFPO-DA HFPO-DA (GenX)PFAS A replacement for PFOA in manufacturing, marketed as safer but still a persistent "forever chemical." Also known as GenX. Health EffectsLiver and kidney effects, reproductive toxicity, immune system effects, and potential cancer risk. EPA Limit10 ppt MCL Common SourcesFluoropolymer manufacturing (used as PFOA replacement), industrial wastewater discharge. | ND | 0.01 | µg/L | PFAS | Not Detected |
| lithium LithiumInorganic A naturally occurring alkali metal found in groundwater. Monitored under UCMR 5 to assess occurrence in drinking water. Health EffectsKidney effects at high doses. Low-level exposure effects under study; some research suggests neurological effects. EPA LimitNo MCL (monitoring only under UCMR 5) Common SourcesNatural mineral deposits, geothermal water, and industrial discharge. | ND | HI | µg/L | PFAS | Not Detected |
| NEtFOSAA | ND | HI | µg/L | PFAS | Not Detected |
| NFDHA | ND | HI | µg/L | PFAS | Not Detected |
| NMeFOSAA | ND | HI | µg/L | PFAS | Not Detected |
| PFBA PFBAPFAS One of the shortest-chain PFAS compounds. Very mobile in water and difficult to remove with standard filtration. Health EffectsThyroid effects, potential developmental toxicity. Shorter half-life in body than long-chain PFAS. EPA LimitNo individual MCL (not yet regulated) Common SourcesDegradation of longer-chain PFAS, industrial discharge, and firefighting foam. | 0.018 | HI | µg/L | PFAS | Detected |
| PFBS PFBSPFAS A short-chain PFAS used as a replacement for PFOS. While it clears the body faster than long-chain PFAS, it still persists in the environment. Health EffectsThyroid effects, reproductive and developmental toxicity, kidney effects. EPA LimitPart of Hazard Index (1.0) Common SourcesIndustrial discharge, firefighting foam, and as a replacement chemical in manufacturing. | 0.035 | HI | µg/L | PFAS | Detected |
| PFDA | ND | HI | µg/L | PFAS | Not Detected |
| PFDoA | ND | HI | µg/L | PFAS | Not Detected |
| PFEESA | ND | HI | µg/L | PFAS | Not Detected |
| PFHpA PFHpAPFAS A medium-chain PFAS compound found in various environmental samples. Less studied than PFOA/PFOS but still considered a contaminant of concern. Health EffectsLiver effects, potential developmental toxicity, and endocrine disruption. EPA LimitPart of Hazard Index (1.0) Common SourcesDegradation of longer-chain PFAS, industrial discharge, and contaminated water sources. | 0.018 | HI | µg/L | PFAS | Detected |
| PFHpS | ND | HI | µg/L | PFAS | Not Detected |
| PFHxA PFHxAPFAS A short-chain PFAS replacement chemical widely used after manufacturers phased out longer-chain PFAS. Very commonly detected in water. Health EffectsLiver and kidney effects, potential thyroid disruption. Considered less toxic than long-chain PFAS but still persistent. EPA LimitNo individual MCL (not yet regulated) Common SourcesIndustrial processes, firefighting foam (AFFF), food packaging, and textile treatment. | 0.037 | HI | µg/L | PFAS | Detected |
| PFHxS PFHxSPFAS A medium-chain PFAS found in firefighting foam and consumer products. It has a long half-life in the human body, similar to long-chain PFAS. Health EffectsImmune system effects, thyroid disruption, and potential reproductive and developmental harm. EPA LimitPart of Hazard Index (1.0) Common SourcesFirefighting foam (AFFF), waterproof textiles, food packaging, and industrial discharge. | 0.080 | HI | µg/L | PFAS | Detected |
| PFMBA | ND | HI | µg/L | PFAS | Not Detected |
| PFMPA | ND | HI | µg/L | PFAS | Not Detected |
| PFNA PFNAPFAS A long-chain PFAS compound used in manufacturing fluoropolymers. It bioaccumulates in the body and is very persistent in the environment. Health EffectsDevelopmental effects, liver toxicity, immune suppression, and potential cancer risk. EPA LimitPart of Hazard Index (1.0) Common SourcesFluoropolymer manufacturing, industrial emissions, and contaminated water sources. | ND | HI | µg/L | PFAS | Not Detected |
| PFOA PFOAPFAS A long-chain PFAS ("forever chemical") once widely used in nonstick coatings and firefighting foam. It persists in the body and environment for years. Health EffectsLinked to kidney and testicular cancer, thyroid disease, elevated cholesterol, and reproductive issues. EPA Limit4.0 ppt MCL Common SourcesIndustrial discharge, firefighting foam (AFFF), nonstick cookware manufacturing, and contaminated groundwater. | 0.018 | 0.004 | µg/L | PFAS | Over MCL |
| PFOS PFOSPFAS A long-chain PFAS compound historically used in stain-resistant coatings and firefighting foam. One of the most studied and persistent PFAS chemicals. Health EffectsLiver damage, immune system suppression, thyroid disruption, increased cholesterol, and potential cancer risk. EPA Limit4.0 ppt MCL Common SourcesFirefighting foam (AFFF), industrial sites, stain-resistant fabric treatments, and contaminated groundwater. | 0.135 | 0.004 | µg/L | PFAS | Over MCL |
| PFPeA PFPeAPFAS A short-chain PFAS compound commonly detected in drinking water. One of the most frequently found PFAS in UCMR 5 monitoring. Health EffectsLess studied than PFOA/PFOS. Potential liver and thyroid effects. Research is ongoing. EPA LimitNo individual MCL (not yet regulated) Common SourcesIndustrial discharge, firefighting foam degradation, and consumer products. | 0.048 | HI | µg/L | PFAS | Detected |
| PFPeS | 0.010 | HI | µg/L | PFAS | Detected |
| PFTA | ND | HI | µg/L | PFAS | Not Detected |
| PFTrDA | ND | HI | µg/L | PFAS | Not Detected |
| PFUnA | ND | HI | µg/L | PFAS | Not Detected |
Lead level trend (90th percentile)
Copper level (90th percentile)
Latest reading: 170.000 mg/L (2022)
EPA action level: 1.3 mg/L
See how Talofofo compares by contaminant
Explore where Talofofo ranks among all Guam cities for specific contaminants.
Water source & infrastructure
Where Talofofo's water comes from
Talofofo's drinking water is drawn from underground aquifers through wells.
Groundwater is naturally filtered through rock and soil layers, generally requiring less treatment than surface water. However, it can contain naturally occurring contaminants like arsenic, radon, and minerals.
Agricultural activity, septic systems, and industrial operations near well fields can introduce nitrates, pesticides, and volatile organic compounds.
The system is operated by state ownership and serves approximately 145,008 people through 2 water systems.
Water bodies near Talofofo
Talofofo is located near 5 notable water bodies. These water bodies contribute to the regional watershed and may indirectly affect groundwater quality.
Water systems serving Talofofo
| System Name | PWSID | Population | Source |
|---|---|---|---|
| GWA NORTHERN WATER SYSTEM | GU0000006 | 139,207 | GW |
| GWA SOUTHERN WATER SYSTEM | GU0000001 | 5,801 | SW |
How Talofofo compares
Full Guam rankings →Talofofo's score of 81.4/100 is on par with the average of 78/100 among major Guam cities. It outscores 6 of 10 nearby cities.
Nearby cities
View Guam rankings →About Talofofo, GU
Wikipedia →Mangilao is a village on the eastern shore of the United States territory of Guam. The village's population has decreased slightly since the island's 2010 census.
Learn more about your water
Guides and resources related to Talofofo's water quality findings.
Explore water quality across Guam
Frequently asked questions
Is Talofofo, GU tap water safe to drink?
Talofofo's water quality earned a grade of B+ (81.4/100). The water generally meets EPA standards and is considered safe for consumption. The city ranks #10 out of 16 cities tested in Guam.
What contaminants are in Talofofo's water?
Lead was measured at 0.9 ppb (90th percentile). 11 PFAS compounds were detected. 27 violations are on record.
How is Talofofo's water quality grade calculated?
The grade is based on four factors: violation history (40%), lead and copper levels (25%), PFAS contamination (25%), and regulatory compliance (10%). The score is also adjusted based on how complete the available data is. See our methodology page for full details.
Do I need a water filter in Talofofo?
PFAS compounds exceed EPA limits — a reverse osmosis or activated carbon filter is recommended.
Where does Talofofo's water come from?
Talofofo's water is sourced from Groundwater. The city has 2 water systems serving approximately 145,008 residents.
What health violations has Talofofo's water system had?
Talofofo has 5 health-based violations on record. The most recent violation was recorded in January 2018. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 2 violations remain unresolved.
Is Talofofo's groundwater at risk of contamination?
Talofofo uses groundwater, which can be affected by naturally occurring contaminants like arsenic, radon, and nitrate, as well as agricultural runoff and industrial activity. The system has 27 violations on record that may relate to groundwater quality. Groundwater systems are generally less susceptible to surface contamination but should be monitored for emerging contaminants like PFAS.
Why does Talofofo have so many PFAS compounds in its water?
11 different PFAS "forever chemical" compounds were detected in Talofofo's water supply during UCMR 5 testing. PFAS contamination often originates from proximity to military installations (AFFF firefighting foam), airports, industrial manufacturing sites, or wastewater treatment facilities. Some levels exceed the 2024 EPA maximum contaminant levels — a reverse osmosis or NSF-certified activated carbon filter is strongly recommended.
How does Talofofo's water compare to other cities?
Talofofo ranks #10 out of 16 cities in Guam (better than 38% of state cities) and #7462 out of 15744 cities nationally (53th percentile). The grade of B+ reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.