Is Alton, NH Tap Water Safe to Drink?
Graded D — but Lead and Copper were detected above EPA limits. Here's what's in the water and how to remove it. What to do next ↓
46.1/100
waterverge.com Alton, NH — Water Quality Report
Alton's drinking water received a grade of D (46.1 out of 100), indicating poor water quality. The city's 4 water systems serve approximately 2,288 residents using groundwater.
Lead levels were measured at 210.0 ppb (90th percentile), which exceeds the EPA action level of 15 ppb. This system has not yet been tested for PFAS under the EPA UCMR 5 program.
The system has 214 violations on record, including 31 health-based violations. 14 remain unresolved.
What to know about Alton's water
Alton ranks #88 out of 119 cities in New Hampshire for water quality, placing it below average in the state.
Alton 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.
Lead levels exceed the EPA action level of 15 ppb, which typically indicates aging lead service lines or lead solder in the distribution system. An NSF 53-certified filter is strongly recommended for drinking and cooking water.
As a small community water system, Alton may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
The system has seen 29 violations in the past five years, suggesting a pattern of compliance challenges that residents should monitor closely.
Water quality score
See methodology →Is Alton, NH water safe to drink?
Alton's drinking water has significant quality concerns based on EPA testing data. With a grade of D (46.1/100), the system has issues across multiple categories. A water filter is recommended for all residents. The city's 4 water systems serve approximately 2,288 residents using groundwater (wells).
Recent water quality updates for Alton
A timeline of significant water quality events, violations, and data updates.
Latest EPA compliance and testing data incorporated into Alton's water quality assessment. Grade: D (46.1/100).
Federal disaster declaration (FEMA DR-4740). Flood event — may have impacted local water infrastructure.
Contaminants: Public Notice.
Contaminants: Arsenic.
Contaminants: Nitrate.
Federal disaster declaration (FEMA DR-4095). Hurricane event — may have impacted local water infrastructure.
Key contaminant findings
Based on the most recent EPA sampling data for Alton's water supply.
Exceeds EPA action level. Lead service line replacement and point-of-use filtration recommended.
Exceeds EPA action level. Copper can leach from household plumbing — flush taps for 30 seconds before drinking.
Violation history
Alton's water system has 214 total violations on record, including 31 health-based violations. 14 remain unresolved. 29 violations were issued in the last 5 years.
Flood & environmental risk
Belknap County has experienced 10 federally declared disasters since 1973. Flooding and severe storms can overwhelm water treatment plants, cause sewage overflows, and introduce agricultural runoff, bacteria, and sediment into drinking water supplies.
Where does Alton's water come from?
Alton's drinking water comes from groundwater (wells), supplied by 4 water systems serving approximately 2,288 people. Groundwater is generally less susceptible to surface contamination but can contain naturally occurring contaminants like arsenic, radon, and nitrate.
What Alton residents can do
Recommended: NSF 53-certified pitcher or under-sink filter. This addresses the specific contaminants found in Alton'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.
Run cold water for 30 seconds before drinking, especially in the morning. Lead and copper leach from household plumbing when water sits in pipes.
Alton's area has a history of flooding. After severe weather, watch for boil water advisories from your local utility.
Data: EPA SDWIS, UCMR 5 (PFAS), FEMA, NOAA. Last updated May 2026.
Top contaminants to know
View all ↓Violation summary
Violations & advisories
Drought conditions
D2 — severe droughtBelknap County is currently in D2 (severe drought) per the U.S. Drought Monitor (week of May 5, 2026). Drought can elevate disinfection-byproduct (TTHM/HAA5) levels and taste/odor issues as utilities draw from lower reservoirs.
Source: U.S. Drought Monitor, updated weekly by NDMC, USDA, and NOAA.
Flood & disaster history
Belknap County has experienced 10 federally declared disasters since 1973. Flooding and severe weather can compromise water treatment infrastructure and introduce contaminants into drinking water supplies.
Recommended water filters
Based on contaminants detected in Alton'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. | 210.0 | 15 | ppb | Inorganic | Over Limit |
| 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. | 2.40 | 1.3 | mg/L | Inorganic | Over Limit |
Lead level trend (90th percentile)
Copper level trend (90th percentile)
See how Alton compares by contaminant
Explore where Alton ranks among all New Hampshire cities for specific contaminants.
Water source & infrastructure
Where Alton's water comes from
Alton'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 local government ownership and serves approximately 2,288 people through 4 water systems.
Water systems serving Alton
| System Name | PWSID | Population | Source |
|---|---|---|---|
| ALTON WATER WORKS | NH0061010 | 1,800 | GW |
| MERRYMEETING MHP | NH0063020 | 265 | GW |
| EAGLES REST MHP | NH0062010 | 138 | GW |
| LAKESIDE AT WINNIPESAUKEE | NH0062050 | 85 | GW |
How Alton compares
Full New Hampshire rankings →Alton's score of 46.1/100 is below the average of 69/100 among major New Hampshire cities. It outscores 1 of 10 nearby cities. 9 of 10 nearby cities score higher.
Nearby cities
View New Hampshire rankings →About Alton, NH
Wikipedia →Alton is a town in Belknap County, New Hampshire, United States. The population was 5,894 at the 2020 census, up from 5,250 at the 2010 census. It is home to Alton Bay State Forest and Mount Major State Forest.
Learn more about your water
Guides and resources related to Alton's water quality findings.
Explore water quality across Belknap
Frequently asked questions
Is Alton, NH tap water safe to drink?
Alton's water quality earned a grade of D (46.1/100). Significant issues have been found. A water filter is strongly recommended. The city ranks #88 out of 119 cities tested in New Hampshire.
What contaminants are in Alton's water?
Lead was measured at 210.0 ppb (90th percentile). 214 violations are on record.
How is Alton'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 Alton?
Yes — lead levels exceed the EPA action level of 15 ppb. We recommend an NSF 53-certified filter or reverse osmosis system. Based on current data, basic filtration should suffice for additional peace of mind.
Where does Alton's water come from?
Alton's water is sourced from Groundwater. The city has 4 water systems serving approximately 2,288 residents.
What health violations has Alton's water system had?
Alton has 31 health-based violations on record. The most recent violation was recorded in March 2023. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 14 violations remain unresolved.
Is Alton's groundwater at risk of contamination?
Alton 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 214 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.
How does Alton's water compare to other cities?
Alton ranks #88 out of 119 cities in New Hampshire (better than 26% of state cities) and #13910 out of 15744 cities nationally (12th percentile). The grade of D reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.