01The verdict: is Wilton water safe?
Wilton's tap water meets most EPA standards but has areas that warrant attention. With a grade of B (75.2/100), some contaminant levels or compliance issues suggest that residents may benefit from additional filtration. The city's 1 water system serves approximately 1,790 residents using groundwater (wells).
Lead is over its legal limit
Measured at 63.0 ppb against the EPA Action Level of 15 ppb. The ledger below shows how far over — and which filter removes it.
See the measurement ↓Monitoring is on schedule
The system is meeting its EPA monitoring and reporting requirements — testing is happening when it should.
See the score ↓A flood-prone service area
9 federal disaster declarations on record. After severe weather, watch for boil-water advisories.
See the risk factors ↓Wilton's drinking water received a grade of B (75.2 out of 100), indicating good water quality. The city's 1 water system serves approximately 1,790 residents using groundwater.
Lead levels were measured at 63.0 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 28 violations on record, including 2 health-based violations. 1 remains unresolved.
Wilton ranks #34 out of 98 cities in New Hampshire for water quality, placing it mid-range in the state. Wilton 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, Wilton may have fewer resources for advanced treatment technologies and infrastructure upgrades compared to larger utilities.
02What's in Wilton's water
Every contaminant flagged in Wilton, on one shared scale: distance to its own legal limit. The red line is the limit — anything past it is out of compliance, and the closer a bar gets, the less headroom the system has.
Over Limit — EPA Action Level: 15 ppb
Exceeds the EPA action level. Lead enters at the service line, not the treatment plant — your address matters more than the city average. Lead service line replacement and an NSF 53-certified point-of-use filter are recommended.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. | 63.0 | 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. | 2.75 | 1.3 | mg/L | Inorganic | Over Limit |
Cities ranked by 90th-percentile lead PF PFAS in New Hampshire
Cities ranked by compounds detected Cu Copper in New Hampshire
Cities ranked by 90th-percentile copper
03Wilton's ten-year track record
Each box is one year. A green check means no EPA violations; a numbered badge counts that year's violations — red if any were health-based, amber if they were monitoring or paperwork issues. The system has 28 violations on record, including 2 health-based violations. 1 remains unresolved.
All ten of the last ten years were clean — no EPA violations recorded for Wilton.
63ppb(1993)
One sampling round on record — 420% of the 15ppb EPA action level. Sampled at higher-risk homes (90th percentile).
2.8mg/L(1993)
One sampling round on record — 212% of the 1.3mg/L EPA action level. Sampled at higher-risk homes (90th percentile).
04Where Wilton's water comes from
Wilton's drinking water is drawn from underground aquifers through wells.
Groundwater
Underground aquifers reached by wells — naturally filtered, but can carry minerals like arsenic and nitrate.
Local treatment
Groundwater generally needs less treatment — typically disinfection and, where needed, mineral removal.
1 system
1 water system, operated under local government ownership.
1,790 people
Residents served across Wilton's service area.
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 1,790 people through 1 water system.
| System name | PWSID | Population | Source |
|---|---|---|---|
| WILTON WATER WORKS | NH2521010 | 1,790 | Groundwater |
Water bodies near Wilton
These water bodies shape the regional watershed and can indirectly affect groundwater quality.
05Pressure on Wilton's watershed
Outside forces that shape what reaches the treatment plant. None of these is a verdict on the tap by itself — but each adds pressure worth knowing about.
Industrial discharge
5 facilities within 10 miles reported 5 lb released to surface water in the latest EPA Toxics Release Inventory. Proximity doesn't equal tap contamination — treatment and hydrology decide — but it's pressure on the watershed.
Flood & storm history
9 federal disaster declarations on record for Hillsborough County. Flooding and severe storms can overwhelm treatment plants, cause sewage overflows, and push runoff into supplies.
Superfund proximity
2 National Priorities List sites within 10 miles. Proximity does not necessarily indicate tap-water contamination — the connection depends on hydrology and treatment.
Drought
Hillsborough County is in D2 (severe drought) per the U.S. Drought Monitor (week of Jul 2026). Drought can raise disinfection-byproduct levels and taste/odor issues as utilities draw from lower reservoirs.
06How Wilton compares
Scores for nearby New Hampshire cities on one line, with the average marked.
dashed line = New Hampshire average (66/100)
Wilton scores 75.2/100 — above the New Hampshire average of 66/100. It outscores 5 of 10 nearby cities. Full New Hampshire rankings →
50.9 / 100ANashua, NH
88.7 / 100DConcord, NH
51.3 / 100BPortsmouth, NH
80.7 / 100AKeene, NH
89.2 / 100BDover, NH
84 / 100
Compare all cities in the county — grades, violations, and contaminant data side by side.→
07What to do at home
Steps matched to what testing actually found in Wilton's water — not generic advice.
Filter drinking & cooking water
NSF 53-certified pitcher or under-sink filter. Lead level (63.0 ppb) exceeds the EPA action level of 15 ppb
Compare tested filters →Flush taps & check your service line
Lead leaches from pipes as water sits. Run cold water 30 seconds before drinking (especially mornings), and ask the utility whether your address still has a lead service line.
Lead risks explained →Watch for Wilton alerts
This area has a history of flood declarations — after severe weather, watch for boil-water advisories from the utility, and check the live alerts on this page.
All water alerts →Frequently asked questions
Is Wilton, NH tap water safe to drink?
Wilton's water quality earned a grade of B (75.2/100). Some concerns have been identified. Consider a water filter for an extra layer of protection. The city ranks #34 out of 98 cities tested in New Hampshire.
What contaminants are in Wilton's water?
Lead was measured at 63.0 ppb (90th percentile). 28 violations are on record.
How is Wilton'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 Wilton?
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 Wilton's water come from?
Wilton's water is sourced from Groundwater. The city has 1 water system serving approximately 1,790 residents.
What health violations has Wilton's water system had?
Wilton has 2 health-based violations on record. The most recent violation was recorded in January 1995. Health-based violations mean the water exceeded EPA maximum contaminant levels (MCLs) for a regulated substance. 1 violation remains unresolved.
Is Wilton's groundwater at risk of contamination?
Wilton 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 28 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 Wilton's water compare to other cities?
Wilton ranks #34 out of 98 cities in New Hampshire (better than 65% of state cities) and #9542 out of 15382 cities nationally (38th percentile). The grade of B reflects the combined assessment of violation history, lead and copper levels, PFAS contamination, and regulatory compliance.
Does Wilton's small water system affect quality?
Wilton's system serves approximately 1,790 residents. Small community water systems (under 3,300 people) may have fewer financial resources for infrastructure upgrades and advanced treatment technologies. However, they are held to the same EPA drinking water standards as larger systems. This system has 28 violations on record.